Multi-setting circuits for the portable dryer

A dryer circuit includes a main circuit and a connection controller. The dryer circuit includes a power unit, a first and second heating units, a first and a second switches, a motor having a fan installed, a resistor, a first diode, and a second diode. The first and the second heating units are coupled to ground respectively through the first and the second switches. The resistor is coupled between the first heating unit and the motor. The first diode is coupled between the second heating unit and the motor. The second diode is coupled between the first heating unit and the motor and in series with the resistor. The connection controller controls the first and the second switches on or off for adjusting the power supplied to the motor, and the first and the second heating units at the same time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a portable dryer, and more particularly, to a multi-setting portable dryer and related circuit design.

2. Description of the Prior Art

The conventional dryer is operable only after establishing connection with an AC power plug through a power cord. The use of the dryer is then limited by the length of the cord to the area that can be reached by the cord from the AC power receptacle. Therefore, it is very inconvenient for traveling purposes, in particular, when traveling in countries where the AC power specifications, such as voltages, cycles, and receptacles vary from one to another. Different converters and transformers are needed if the user wants to use a conventional dryer. Furthermore, since the conventional AC-powered dryers are powered by AC currents with sinusoidal amplitudes, most use a diode to control the generation of heat. When the switch is shifted to a low heat setting, the one-way conduction property of the diode filters out a half cycle of the AC current that passes through the heating filament. When the switch is shifted to a high heat setting, the current to the heating filament does not go through the diode so that heat can be generated at full output. At the same time, in order to provide a DC current to the motor, an additional bridge rectifier has to be employed to supply the needed DC power.

SUMMARY OF THE INVENTION

The present invention provides a dryer circuit. The dryer circuit comprises a main circuit and a connection controller. The main circuit comprises a power unit, a first heating unit, a second heating unit, a fan motor, a diode, and a resistor. The power unit comprises a first end for providing a first predetermined voltage, and a second end for providing a second predetermined voltage. The first heating unit comprises a first end coupled to the first end of the power unit, and a second end. The second heating unit comprises a first end coupled to the first end of the power unit, and a second end. The fan motor comprises a first end coupled to the first end of the power unit, and a second end. The diode is coupled between the second end of the second heating unit and the second end of the fan motor. The resistor is coupled between the second of the first heating unit and the second end of the fan motor. The connection controller is coupled to the second end of the first heating unit, the second end of the second heating unit, and the second end of the power unit for switching coupling of the second end of the first heating unit to the second end of the power unit and switching coupling of the second end of the second heating unit to the second end of the power unit.

The present invention further provides a dryer circuit. The dryer circuit comprises a main circuit, and a connection controller. The main circuit comprises a power unit, a first heating unit, a second heating unit, a fan motor, a diode, and a resistor. The power unit comprises a first end for providing a first predetermined voltage, and a second end for providing a second predetermined voltage. The first heating unit comprises a first end, and a second end coupled to the second end of the power unit. The second heating unit comprises a first end coupled to the first end of the first heating unit, and a second end. The fan motor comprises a first end coupled to the first end of the first heating unit, and a second end. The diode is coupled between the second end of the second heating unit and the second end of the fan motor. The resistor is coupled between the second of the first heating unit and the second end of the fan motor. The connection controller is coupled to the power unit, the first heating unit, and the second heating unit, for switching coupling between the first heating unit, the power unit, and the second heating unit.

The present invention further provides a dryer circuit. The dryer circuit comprises a main circuit, and a connection controller. The main circuit comprises a power unit, a first heating unit, a second heating unit, a fan motor, a diode, and a resistor. The power unit comprises a first end for providing a first predetermined voltage, and a second end for providing a second predetermined voltage. The first heating unit comprises a first end coupled to the first end of the power unit, and a second end. The second heating unit comprises a first end coupled to the first end of the first heating unit, and a second end. The fan motor comprises a first end coupled to the first end of the first heating unit, and a second end. The diode is coupled between the second end of the second heating unit and the second end of the fan motor. The resistor is coupled between the second of the first heating unit and the second end of the fan motor. The connection controller is coupled to the power unit, the first heating unit, and the second heating unit, for switching coupling between the first heating unit, the power unit, and the second heating unit.

DETAILED DESCRIPTION

The present invention utilizes a portable electrical power source (e.g., battery). Therefore, the portable dryer circuit of the present invention does not need to connect to an AC receptacle. Furthermore, the present invention provides innovative circuit designs to control the power consumed by the motor and the power consumed by the heating units at the same time for generating airflow at the desired heat output.

Please refer toFIG. 1.FIG. 1is a diagram illustrating the dryer circuit100according to a first embodiment of the present invention. As shown inFIG. 1, the dryer circuit100comprises a main circuit110and a connection controller120. The main circuit110comprises a power unit B, a motor M (including a fan), two diodes D1and D2, two heating units HG1and HG2, a resistor R1, and four nodes N1, N2, N3, and N4. However, the node N2is equivalent to the node N4electrically. The power unit B comprises a positive end for providing a voltage VB(20 volts), and a negative end for serving as a ground end (0 volt). The heating units HG1and HG2generate heat according to power consumed by the heating units HG1and HG2, respectively. The motor M (including a fan) generates airflow with a volume according to the power consumed by the motor M.

Between the positive end of the power unit B and node N1, the heating unit HG1, the motor M, the diode D2, and the resistor R1form a circuit group G1. In the circuit group G1, the motor M is coupled to the diode D2and the resistor R1, which the diode D2and the resistor R1are coupled in series, and the motor is further coupled to the heating unit HG1in parallel.

Between the positive end of the power unit B and node N3, the heating unit HG2, the motor M, and the diode D1, form a circuit group G2. In the circuit group G2, the motor M and the diode D1are coupled in series, and the motor M is further coupled to the heating unit HG2in parallel.

The connection controller120controls the connection between the nodes N1and N2and the connection between the nodes N3and N4, respectively. Therefore, by controlling the current to flow through the circuit groups G1, the circuit group G2, or both the circuit groups G1and G2, different modes of the dryer circuit100are achieved.

The following are to define four operating modes, mode0,1,2, and3of the present invention. In mode0, the connection controller120disconnects both the nodes N1from N2and the nodes N3from N4. Therefore, no current flows through the motor M, the heating units HG1and HG2. In mode1, the connection controller120connects the node N1to the node N2, which means current only flows through the circuit group G1. In mode2, the connection controller120connects the node N3to the node N4, which means current only flows through the circuit group G2. In mode3, the connection controller120connects the node N1to the node N2, and connects the node N3to the node N4, which means current flows through both the circuit group G1and circuit group G2.

Please refer toFIG. 2.FIG. 2is a diagram illustrating the dryer circuit100operating in mode1. As shown inFIG. 2, the connection controller120connects the node N1to the node N2, but disconnects the node N3from the node N4. The diode D1, instead of filtering a half cycle of the AC current as utilized in a traditional hair dryer, blocks the DC current flowing through the heating unit HG2in mode1operation. Therefore, the electric power provided by the power unit B passes through the circuit group G1, and the voltage on the heating unit HG1equals to the voltage VB. Neglecting the small voltage drops over the diode D2, the voltage VBis shared by the resistor R1and the motor M according to their impedances respectively.

In mode1, the power consumed respectively by the heating unit HG1and the motor M are calculated by the following equations:
PHG1=VB2/(RHG1)   (1)
VM=VB×[RM/(RM+R1)]  (2)
PM=VM2/RM=VB2×RM/(RM+R1)2(3)

wherein VMrepresents the voltage on the motor M, PHG1and PMrepresent the power consumed by the heating unit HG1and the motor M respectively, and RHG1, R1and RMrepresent the impedance of the heating unit HG1, resistor R1and the motor M respectively.

Please refer toFIG. 3.FIG. 3shows the calculation of the power consumptions on the components in the main circuit110in mode1. As shown inFIG. 3, the power to the motor M is 25.9 Watt, and the total power of the main circuit110is 236.3 Watt.

Please refer toFIG. 4.FIG. 4is a diagram illustrating the dryer circuit100operating in mode2. As shown inFIG. 4, the connection controller120connects the node N3to the node N4, but disconnects the node N1from the node N2. The diode D2blocks the DC current flowing through the heating unit HG1in mode2operation. Therefore, the electric power provided by the power unit B passes through the circuit group G2, and the voltage on the heating unit HG2equals to the voltage VB. Neglecting the small voltage drops over the diode D1, the voltage on the motor M equals to the voltage VB.

In mode2, the power consumed respectively by the heating unit HG2and the motor M are calculated by the following equations:
PHG2=VB2/(RHG2)   (4)
PM=VB2/RM(5)

wherein the PHG2represents the power consumed by the heat unit HG2, and RHG2represents the impedance of the heat unit HG2.

Please refer toFIG. 5.FIG. 5shows the calculation of the power consumptions on the components in the main circuit110in mode2. As shown inFIG. 5, the power to the motor M is 50 Watt and the total power of the main circuit110is 250 Watt. The total power of the main circuit110has slight difference between in mode2and mode1. However, the power to the motor M in mode2is almost twice as much as that in mode1.

Please refer toFIG. 6.FIG. 6is a diagram illustrating the dryer circuit100operating in mode3. As shown inFIG. 6, the connection controller120connects the node N1to the node N2, and connects the node N3to the node N4. Therefore, the electric power provided by the power unit B passes through both the circuit group G1and circuit group G2, and the voltage on the heating unit HG1equals to the voltage VBand the voltage on the heating unit HG2equals to the voltage VB. Because the resistor R1is disposed in the circuit group G1, the current flowing through the resistor R1and the diode D2can be ignored in mode3. Neglecting the small voltage drops over the diode D1, the voltage on the motor M equals to the voltage VB.

In mode3, the power consumed respectively by the heating units HG1and HG2and the motor M are calculated by the following equations:
PHG1=VB2/(RHG1)   (6)
PHG2=VB2/(RHG2)   (7)
PM=VM2/RM=VB2/RM(8)

wherein the PHG1and PHG2respectively represent the power consumed by the heat units HG1and HG2, RHG1and RHG2respectively represent the impedances of the heat units HG1and HG2, PMrepresents the power consumed by the motor M, and RMrepresents the impedance of the motor M.

Please refer toFIG. 7.FIG. 7shows the calculation of the power consumptions on the components in the main circuit110in mode3. As shown inFIG. 7, the power to the motor M is 50 Watt, and the total power of the main circuit110is 450 Watt. Both the power to the motor M and the total power of the main circuit110in mode3are nearly twice as much as those in mode1.

Please refer toFIG. 8.FIG. 8is a diagram illustrating a first connection controller800of the first embodiment of the present invention. As shown inFIG. 8, the connection controller800comprises two switches SW1and SW2respectively for controlling the connection between nodes N1and N2and the connection between nodes N3and N4. The switches SW1and SW2are respectively controlled to achieve the operation of the dryer circuit100in modes0,1,2, and3. The switches SW1and SW2can be mechanical switches.

Please refer toFIG. 9.FIG. 9is a diagram illustrating the connection controller801based on the connection controller800and utilizing a slide switch SWT of the present invention. As shown inFIG. 9, the slide switch SWT comprises a base H, a slide button T, and two conducting pads P1and P2. The slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N3and N4. The conducting pads P3and P4are disposed for the nodes N1and N2and are both shaped as dots. The conducting pads P5and P6are disposed for the nodes N3and N4and are shaped as lines. By moving the slide button T of the slide switch SWT to different positions, the dryer circuit100can operate in modes0,1,2, and3.

InFIG. 9, by default setting, the connection controller801achieves mode0for the dryer circuit100by disposing the slide button T in a position so that both the conducting pads P1and P2do not contact with the pads P3, P4, P5, and P6.

Please refer toFIG. 10.FIG. 10is a diagram illustrating the connection controller801in mode1. As shown inFIG. 10, the slide button T moves downward so that the conducting pad P2contacts with the conducting pads P3and P4in order to establish the connection between the nodes N1and N2. Therefore, the nodes N1and N2are short-circuited by the conducting pad P2, and consequently the dryer circuit100operates in mode1.

Please refer toFIG. 11.FIG. 11is a diagram illustrating the connection controller801in mode2. As shown inFIG. 11, the slide button T moves further downward so that the conducting pad P2shifts away from pads P3and P4and contacts with the conducting pads P5and P6to establish the connection between the nodes N3and N4. Therefore, the nodes N3and N4are short-circuited by the conducting pad P2, and consequently the dryer circuit100operates in mode2.

Please refer toFIG. 12.FIG. 12is a diagram illustrating the connection controller801in mode3. As shown inFIG. 12, the slide button T moves further downward so that the conducting pad P2still contacts with the conducting pads P5and P6in order to establish the connection between the nodes N3and N4, and the conducting pad P1contacts with the conducting pads P3and P4in order to establish the connection between the nodes N1and N2, Therefore, the nodes N1and N2are short-circuited by the conducting pad P1, the nodes N3and N4are short-circuited by the conducting pad P2, and consequently the dryer circuit100operates in mode3.

Please refer toFIG. 13.FIG. 13is a diagram illustrating another connection controller1300of the first embodiment of the present invention. As shown inFIG. 13, the connection controller1300comprises a transistor Q1controlled by a switch SW3for the connection between the nodes N1and N2, and a transistor Q2controlled by a switch SW4for the connection between the nodes N3and N4. The transistor Q1connects the node N1to node N2when the switch SW3is short-circuited to the power unit B for transmitting the voltage VBso that the control end of the transistor Q1receives the voltage VBfrom the power unit B. The transistor Q1disconnects the node N1from the node N2when the switch SW3is open (no voltage is received on the control end of the transistor Q1). The transistor Q2connects the node N3to the node N4when the switch SW4is short-circuited to the power unit B for transmitting the voltage VBso that the control end of the transistor Q2receives the voltage VBfrom the power unit B. The transistor Q2disconnects the node N3from the node N4when the switch SW4is open (no voltage is received on the control end of the transistor Q2). Additionally, the voltage transmitted to the control ends of the transistors Q1and Q2for controlling the transistors Q1and Q2can be positive or negative, depending on the transistors being forward-biased or reverse-biased. The switches SW3and SW4are respectively controlled to achieve the operation of the dryer circuit100in modes0,1,2, and3.

Please refer toFIG. 14.FIG. 14is a diagram illustrating the connection controller1301based on the connection controller1300and utilizing a slide switch SWT of the present invention. As shown inFIG. 14, the slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N3and N4. The dryer circuit100operates in modes0,1,2, and3according to the movement of the slide button T of the slide switch SWT as described fromFIG. 9toFIG. 12and the related description is omitted.

Please refer toFIG. 15.FIG. 15is a diagram illustrating another connection controller1500of the first embodiment of the present invention. As shown inFIG. 15, the connection controller1500comprises two transistors Q1and Q2both controlled by a slide switch SWT, three pads P6, P8and P10connected to the power unit B, a pad P5connected to the control end of transistor Q1, a pad P7connected to the control end of transistor Q2, and a pad P9connected to both the control ends of transistor Q1and transistor Q2through the diodes D3and D4respectively. The slide switch SWT comprises a base H, a slide button T, and a conducting pad P1.

When the slide button T of the slide switch SWT shifts to the position for mode1, the pad P5and the pad P6are short-circuited by the conducting pad P1, so the control end of the transistor Q1receives the voltage VBfrom the power unit B. Therefore, the transistor Q1connects the node N1to the node N2. The diode D3prevents the transistor Q2from receiving the voltage VBfrom the power unit B when the pad P5and the pad P6are short-circuited.

When the slide button T of the slide switch SWT shifts to the position for mode2, the pad P7and the pad P8are short-circuited by the conducting pad P1, so the control end of the transistor Q2receives the voltage VBfrom the power unit B. Therefore, the transistor Q2connects the node N3to the node N4. The diode D4prevents the transistor Q1from receiving the voltage VBfrom the power unit B when the pad P7and the pad P8are short-circuited.

When the slide button T of slide switch SWT shifts to the position for mode3, the pad P9and the pad P10are short-circuited by the conducting pad P1, so both the control ends of the transistors Q1and Q2receive the voltage VBfrom the power unit B. Therefore, the transistor Q1connects the node N1to the node N2and the transistor Q2connects the node N3to the node N4.

In summary, the dryer circuit100can operate in modes0,1,2, and3by shifting the slide button T of the slide switch SWT to different positions.

Please refer toFIG. 16.FIG. 16is a diagram illustrating another dryer circuit1600which is electrically equivalent to the dryer circuit100of the first embodiment of the present invention. As shown inFIG. 16, the dryer circuit1600comprises a main circuit1610and a connection controller1620. The main circuit1610comprises a power unit B, a motor M (including a fan), two diodes D1and D2, two heating units HG1and HG2, a resistor R1, and three nodes N1, N2, and N4.

Between the node N2and the negative end of the power unit B, the heating unit HG1, the motor M, the diode D2, and the resistor R1form a circuit group G1. Between the node N4and the negative end of the power unit B, the heating unit HG2, the motor M, and the diode D1, form a circuit group G2.

The connection controller1620controls the connection between the nodes N1and N2, and the connection between the nodes N1and N4, respectively. Therefore, by controlling the current to flow through the circuit groups G1, the circuit group G2, or both the circuit groups G1and G2, different modes of the dryer circuit100are achieved.

Utilizing the connection controller1620, the main circuit1610can operate in mode0,1,2and3. Though the dispositions of all components of the dryer circuit1600are rearranged and different from those of the dryer circuit100, the dryer circuit1600is electrically equivalent to the dryer circuit100.

Please refer toFIG. 17.FIG. 17is a diagram illustrating a second embodiment of the present invention. As shown inFIG. 17, the dryer circuit1700comprises a main circuit1710and a connection controller1720. The main circuit1710comprises a power unit B, a motor M (including a fan), a diode D1, two heating units HG1and HG2, a resistor R1, and four nodes N1, N2, N3, and N4. The power unit B provides a voltage VB. The heating units HG1and HG2generate heat according to power consumed by the heating units HG1and HG2respectively. The motor M (including a fan) generates airflow with a volume according to the power consumed by the motor M.

Between the node N2and the negative end of the power unit B, the heating unit HG1, the motor M, and the resistor R1form a circuit group G3. In the circuit group G3, the motor M and the resistor R1are coupled in series, and the motor M and the heating unit HG1are coupled in parallel.

Between the nodes N2and N3, the heating unit HG2, the motor M, and the diode D1, form a circuit group G4. In the circuit group G4, the motor M and the diode D1are coupled in series, and the motor M and the heating unit HG2are coupled in parallel.

The connection controller1720controls the connection between the nodes N1and N2, and the connection between the nodes N3and N4, respectively. Therefore, by controlling the current to flow through the circuit groups G3, or both the circuit groups G3and G4, different modes of the dryer circuit1700are achieved.

When the dryer circuit1700operates in mode0, the main circuit1710is turned off. The connection controller1720disconnects the connection between the nodes N1and N2. Therefore, no current flows through the motor M, the heating units HG1and HG2.

However, when the connection controller1720disconnects the node N1from the node N2and connects the node N3to the node N4, no current flows through the circuit group G4. Therefore, the dryer circuit1700does not operate in mode2in the second embodiment of the present invention.

Please refer toFIG. 18.FIG. 18is a diagram illustrating the dryer circuit1700operating in mode1. As shown inFIG. 18, the connection controller1720connects the node N1to the node N2, but disconnects the node N3from the node N4. The diode D1blocks the DC current flowing through the heating unit HG2in mode1operation. Therefore, the electric power provided by the power unit B only passes through the circuit group G3, the voltage on the heating unit HG1equals to the voltage VB, and the resistor R1and the motor M share the voltage VBaccording to their impedances respectively.

In the mode1, the power consumed respectively by the heating unit HG1and the motor M are calculated by the following equations:
PHG1=VB2/(RHG1)   (9)
VM=VB×[RM/(RM+R1)]  (10)
PM=VM2/RM=VB2×RM/(RM+R1)2(11)

wherein VMrepresents the voltage on the motor M, PHG1and PMrepresent the power consumed by the heating unit HG1and the motor M respectively, and RHG1, R1and RMrepresent the impedance of the heating unit HG1, resistor R1and the motor M respectively. The calculation of the power consumptions on the components in the main circuit1710in mode1is similar toFIG. 3and is omitted.

Please refer toFIG. 19.FIG. 19is a diagram illustrating the dryer circuit1700operating in mode3. As shown inFIG. 19, the connection controller1720connects the node N1to the node N2, and connects the node N3to the node N4. Therefore, the electric power provided by the power unit B passes through both the circuit group G3and G4. Because the resistor R1is disposed in the circuit group G3, the current flowing through the resistor R1can be ignored in mode3. Neglecting the small voltage drops over the diode D1, the voltage on the motor M equals to the voltage VB.

In mode3, the power consumed respectively by the heating units HG1and HG2and the motor M are calculated by the following equations:
PHG1=VB2/(RHG1)   (12)
PHG2=VB2/(RHG2)   (13)
PM=VM2/RM=VB2/RM(14)

wherein the PHG1and PHG2respectively represent the power consumed by the heat units HG1and HG2, and RHG1and RHG2respectively represent the equivalent impedances of the heat units HG1and HG2. The calculation of the power consumptions on the components in the main circuit1710in mode3is similar toFIG. 7and is omitted.

Please refer toFIG. 20.FIG. 20is a diagram illustrating a first connection controller2000of the second embodiment of the present invention. As shown inFIG. 20, the connection controller2000comprises two switches SW1and SW2respectively for the connection between the nodes N1and N2and the connection between the nodes N3and N4. The switches SW1and SW2are respectively controlled to achieve the operation of the dryer circuit1700in modes0,1and3. In the connection controller2000, the switches SW1and SW2can be mechanical switches.

Please refer toFIG. 21.FIG. 21is a diagram illustrating the connection controller2001based on the connection controller2000and utilizing a slide switch SWT of the present invention. As shown inFIG. 21, the slide switch SWT comprises a base H, a slide button T and two conducting pads P1and P2. The slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N3and N4. The conducting pads P3and P4are disposed for the nodes N1and N2, and the conducting pads P5and P6are disposed for the nodes N3and N4. The dryer circuit1700operates in modes0,1and3according to the movement of the slide button T of the slide switch SWT.

InFIG. 21, by default setting, the connection controller2001achieves mode0operation for the dryer circuit1700by disposing the slide button T in a position that both the conducting pads P1and P2do not contact with the pads P3, P4, P5, and P6.

Please refer toFIG. 22.FIG. 22is a diagram illustrating the connection controller2001in mode1. As shown inFIG. 22, the slide button T moves downward so that the conducting pad P2contacts with the conducting pads P3and P4in order to establish the connection between the nodes N1and N2. Therefore, the nodes N1and N2are short-circuited by the conducting pad P2, and consequently the dryer circuit1700operates in mode1.

Please refer toFIG. 23.FIG. 23is a diagram illustrating the connection controller2001in mode3. As shown inFIG. 23, the slide button T moves further downward so that the conducting pad P2contacts with the conducting pads P5and P6in order to establish the connection between the nodes N3and N4, and the conducting pad P1contacts with the conducting pads P3and P4in order to establish the connection between the nodes N1and N2. Therefore, the nodes N1and N2are short-circuited by the conducting pad P1, the nodes N3and N4are short-circuited by the conducting pad P2, and consequently the dryer circuit1700operates in mode3.

Please refer toFIG. 24.FIG. 24is a diagram illustrating another connection controller2400of the second embodiment of the present invention. As shown inFIG. 24, the connection controller2400comprises a transistor Q1controlled by a switch SW3for the connection between the nodes N1and N2, and a transistor Q2controlled by a switch SW4for the connection between the nodes N3and N4. The transistor Q1connects the node N1to the node N2when the switch SW3is short-circuited for transmitting the voltage VBfrom the power unit B and the control end of the transistor Q1receives the voltage VBfrom the power unit B. The transistor Q2connects the node N3to the node N4when the switch SW4is short-circuited for transmitting the voltage VBfrom the power unit B and the control end of the transistor Q2receives the voltage VBfrom the power unit B. The voltages on the control ends of the transistors Q1and Q2for actuating the transistors Q1and Q2can be positive or negative, depending on the transistors being forward-biased or reverse-biased. The switches SW3and SW4are coupled in parallel for being respectively controlled in order to achieve the operation of the dryer circuit1700in modes0,1and3.

Please refer toFIG. 25.FIG. 25is a diagram illustrating the connection controller2401based on the connection controller2400and utilizing a slide switch SWT of the present invention. As shown inFIG. 25, the slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N3and N4. The dryer circuit1700operates in modes0,1and3according to the movement of the slide button T of the slide switch SWT as described fromFIG. 21toFIG. 23and the related description is omitted.

Please refer toFIG. 26.FIG. 26is a diagram illustrating another connection controller2600of the second embodiment of the present invention. As shown inFIG. 26, the connection controller2600comprises two transistors Q1and Q2both controlled by a slide switch SWT, a pad P2connected to the power unit B, a pad P1connected to the control end of transistor Q1, and a pad P3connected to the control end of transistor Q1through diode D3and to the control end of transistor Q2. The slide switch SWT comprises a base H, a slide button T, and a conducting pad C.

By default setting, the connection controller3200achieves mode0operation for the dryer circuit1700by disposing the slide button T in a position that conducting pad C contacts with no pads but only the pad P1.

When the slide button T of the slide switch SWT shifts to the position for mode1, the pad P1and the pad P2are short-circuited by the conducting pad C, so the control end of the transistor Q1receives the voltage VBfrom the power unit B. Therefore, the transistor Q1connects the node N1to the node N2. The diode D3prevents the transistor Q2from receiving the voltage VBfrom the power unit B when the pad P1and the pad P2are short-circuited.

When the slide button T of the slide switch SWT shifts to the position for mode3, the pad P2and the pad P3are short-circuited by the conducting pad C, so both the control ends of the transistors Q1and Q2receive the voltage VBfrom the power unit B. Therefore, the transistor Q1connects the node N1to the node N2and the transistor Q2connects the node N3to the node N4.

In summary, the dryer circuit1700can operate in modes0,1, and3by shifting the slide button T of the slide switch SWT to different positions.

Please refer toFIG. 27.FIG. 27is a diagram illustrating another connection controller2700of the second embodiment of the present invention. As shown inFIG. 27, the connection controller2700comprises a transistor Q1controlled by a switch SW3for the connection between the nodes N1and N2, and a transistor Q2controlled by a switch SW4for the connection between the nodes N3and N4. The transistor Q1connects node N1to node N2when the switch SW3is short-circuited for transmitting the voltage VBfrom the power unit B and the control end of the transistor Q1receives the voltage VBfrom the power unit B. The transistor Q2connects node N3to the node N4only when both switch SW3and switch SW4are short-circuited for transmitting the voltage VBfrom the power unit B and the control end of the transistor Q2receives a voltage from the power unit B. The voltages on the control ends of the transistors Q1and Q2can be positive or negative, depending on the transistors being forward-biased or reverse-biased. The switches SW3and SW4are coupled in series for being respectively controlled to achieve the operation of the dryer circuit1700in modes0,1and3.

Please refer toFIG. 28.FIG. 28is a diagram illustrating the connection controller2701based on the connection controller2700and utilizing a slide switch SWT of the present invention. As shown inFIG. 28, the slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N3and N4. The dryer circuit1700operates in modes0,1and3according to the movement of the button T of the slide switch SWT as described fromFIG. 21toFIG. 23and the related description is omitted.

Please refer toFIG. 29.FIG. 29is a diagram illustrating a third embodiment of the present invention. As shown inFIG. 29, the dryer circuit2900comprises a main circuit2910and a connection controller2920. The main circuit2910comprises a power unit B, a motor M (including a fan), a diode D1, two heating units HG1and HG2, a resistor R1, and three nodes N1, N2, and N3. The power unit B provides a voltage VB. The heating units HG1and HG2generate heat according to power consumed by the heat units HG1and HG2respectively. The motor M (including a fan) generates airflow with a volume according to the power consumed by the motor M.

Between the positive end of the power unit B and the node N1, the heating unit HG1, the motor M, and the resistor R1form a circuit group G3. In the circuit group G3, the motor M and the resistor R1are coupled in series, and the motor M and the heating unit HG1are coupled in parallel.

Between the positive end of the power unit B and the node N3, the heating unit HG2, the motor M, and the diode D1, form a circuit group G4. In the circuit group G4, the motor M and the diode D1are coupled in series, and the motor M and the heating unit HG2are coupled in parallel.

The connection controller2920controls the connection between the nodes N1and N2, and the connection between the nodes N2and N3, respectively. Therefore, by controlling the current to flow through the circuit groups G3, or both the circuit groups G3and G4, different modes of the dryer circuit2900are achieved.

The dryer circuit2900utilizes the connection controller2920to perform the same operating modes0,1and3as described fromFIG. 17toFIG. 19for the dryer circuit1700and the related description is omitted. The calculations of the power consumptions on the components in the main circuit2910in modes1and3are similar toFIG. 3andFIG. 7, which are also omitted.

Please refer toFIG. 30.FIG. 30is a diagram illustrating a first connection controller2901of the third embodiment of the present invention. As shown inFIG. 30, the slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N2and N3. The dryer circuit2900operates in modes0,1and3according to the movement of the slide button T of the slide switch SWT as described fromFIG. 21toFIG. 23and the related description is omitted.

Please refer toFIG. 31.FIG. 31is a diagram illustrating another connection controller3100of the third embodiment of the present invention. As shown inFIG. 31, the connection controller3100comprises a transistor Q1for the connection between the nodes N1and N2, a transistor Q2for the connection between the nodes N2and N3, and a slide switch SWT for controlling both transistors Q1and Q2. The voltage on the control ends of the transistors Q1and Q2can be positive or negative, depending on the transistors being forward-biased or reverse-biased. The dryer circuit2900operates in modes0,1and3according to the movement of the slide switch SWT also as described fromFIG. 21toFIG. 23and the related description is omitted.

Please refer toFIG. 32.FIG. 32is a diagram illustrating another connection controller3200of the third embodiment of the present invention. As shown inFIG. 32, the connection controller3200comprises two transistors Q1and Q2both controlled by a slide switch SWT, a pad P2connected to the power unit B, a pad P1connected to the control end of transistor Q1, and a pad P3connected to the control end of transistor Q1through diode D3and to the control end of transistor Q2. The slide switch SWT comprises a base H, a slide button T, and a conducting pad C. The dryer circuit2900operates in modes0,1and3according to the movement of the slide button T of the slide switch SWT as described inFIG. 26and the related description is omitted.

Please refer toFIG. 33.FIG. 33is a diagram illustrating another connection controller3300of the third embodiment of the present invention. As shown inFIG. 33, the connection controller3300comprises a transistor Q1controlled by a switch SW3for the connection between the nodes N1and N2, and a transistor Q2controlled by a switch SW4for the connection between the nodes N2and N3. The switches SW3and SW4are coupled in series for respectively being controlled to achieve the operation of the dryer circuit2900in modes0,1and3as described inFIG. 27and the related description is omitted.

Please refer toFIG. 34.FIG. 34is a diagram illustrating the connection controller3301based on the connection controller3300and utilizing a slide switch SWT of the present invention. As shown inFIG. 34, the slide switch SWT is disposed for controlling the connection between the nodes N1and N2and the connection between the nodes N2and N3. The dryer circuit2900operates in modes0,1and3according to the movement of the slide button T of the slide switch SWT as described fromFIG. 21toFIG. 23and the related description is omitted.

Please refer toFIG. 35.FIG. 35is a diagram illustrating alternative embodiment of the second embodiment of the present invention. As shown inFIG. 35, the dryer circuit3500is similar to the dryer circuit1700inFIG. 17, but the difference between the two dryer circuits is: the node N1is disposed at the second end of the power unit B, and the node N2is disposed at the second end of the heating unit HG1.

Additionally, the power unit mentioned in the present invention can be realized with battery, rechargeable battery, fuel cell, micro-engine, or any device providing electric power and should not be limited to the embodiments mentioned above. The heating units mentioned in the present invention can be realized with heating filaments, or any devices with impedance for generating heat by consuming electric power and should not be limited to the embodiment mentioned above. The transistors mentioned in the present invention can be realized with any electronic switches including but not limited to MOSFET (metal-oxide semiconductor field-effect transistor), JFET (junction field-effect transistor), SCR (silicon-controlled rectifier), UJT (uni-junction transistor) and so on. Further, the resistor mentioned in the present invention also can be replaced by and utilized as a heating unit, and the slide switch mentioned in the present invention also can be replaced with other kinds of switches such as rotary switches or push-button switches.

To sum up, the present invention provides various innovative dryer circuits to achieve multi-setting of the portable dryer. Particularly, the dry circuits utilize the connection controller to control the power consumed by the motor and the power consumed by the heating units at the same time for generating various volume of airflow at the desired heat output.