Patent Abstract:
A temperature controller module for electronically controlling the temperature of a device, such as a pump laser or laser diode, controls the device temperature based on low heat dissipation inductors and current sources. The temperature controller module shuts off the thermoelectric cooler when the temperature of the laser exceeds a predetermined amount. Further, the temperature controller module is integrated in a compact, self-contained modular form to allow use in space critical applications.

Full Description:
RELATED APPLICATIONS 
   The present application is related to and claims the benefit of U.S. Provisional Application No. 60/346,737 filed Jan. 8, 2002, in the names of RENFENG GAO, RENYUAN GAO, JOHN FINN, and JOSEPH CHANG, the entire contents of which are relied on and fully incorporated herein by reference. 

   GOVERNMENT LICENSE RIGHTS 
   The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Contract No. N00014-00C-0117 awarded by the U.S. Navy. 

   FIELD OF THE INVENTION 
   The present invention relates generally to the control of active components, and more particularly to a method and system for controlling the temperature of devices, such as lasers and laser diodes, by using low heat dissipation current sources with low heat dissipation inductors integrated into a single temperature controller module. 
   BACKGROUND OF THE INVENTION 
   Presently, controlling the temperature of devices, such as semiconductor devices, based on thermoelectric cooling is applied to a wide range of devices and systems. For example, in optical communication systems it is important to monitor and control the temperature of devices so they remain operational and do not cause damage to other components. Such devices may include laser diodes, semiconductor optical amplifiers, erbium doped optical amplifiers, optical wavelength division multiplexers, and fiber Bragg gratings. A thermoelectric cooler (TEC) may be used to perform the function of cooling such devices. In addition, TECs are used in applications in many industries and fields, including biomedical devices, semiconductor microelectronic devices, and devices involving aerospace applications. 
   A TEC may be operated by a controller that drives the TEC. The operation of the controller for the TEC may rely on feed-back loop based electronic drivers that provide a controlled electrical current injection to the TEC. Generally, designing analog control loops for active optical devices involves the use of power operational amplifiers and power transistors. However, using power operational amplifiers and transistors has several drawbacks. For example, their use is costly. Second, power operational amplifiers and power transistors use a large amount of printed circuit board area. Therefore, it is inefficient to use these devices in applications where space is critical such as, for example, in telecommunications systems, pump laser controllers, continuous wave distributed feedback (CW DFB) laser controllers, Bragg gratings, temperature controllers, heater element controllers, thermoelectric controllers, L band drivers, C band drivers, S Band drivers, Raman amplifier controls, and semiconductor optical amplifier (SOA) driver controls. Third, using power operational amplifiers and power transistors gives rise to thermal inefficiencies, which may lead to the degradation of the components of the application. Since many applications using temperature controllers require low power consumption as well as compact size, the existing hardware is difficult to integrate into these applications. It is therefore desirable to provide a temperature controller module for lasers, laser diodes, and others of the above mentioned components, that overcomes the above described problems and disadvantages of present systems. 
   SUMMARY OF THE INVENTION 
   There is provided a method for electronically controlling a temperature of a device. A variable current is supplied to a cooler, which provides heat transfer away from the device. The temperature of the device is determined. An amount of current to be supplied to the cooler in response to the device temperature is determined. The device temperature is compared against a predetermined temperature range. The cooler is supplied with the determined amount of current by at least one current source when the device temperature is within the first predetermined temperature range and the current is sufficiently blocked to render the cooler inoperable if the device temperature is outside the predetermined temperature range. Each current source is further coupled to at least one inductor. 
   There is also provided a system for electronically controlling a temperature of a device by providing a current to a temperature regulating element. The system comprises a temperature detector to produce a signal representative of the device temperature; a driver to determine an amount of current, in response to the signal, to be supplied to the temperature regulating element; and a temperature controller, including at least one current source and at least one associated inductor, to provide the current in response to the determination by the driver. 
   There is also provided a system for electronically controlling a temperature of a device by providing a variable current to a cooler. The system comprises a temperature detector to produce a signal representative of the device temperature; a cooler driver, responsive to the signal, to determine an amount of current to be supplied to the cooler; and a temperature controller, coupled to the cooler driver and including at least one current source, to provide the determined amount of current to the cooler. The determined amount of current varies in response to the signal and is provided to the cooler when the current source is enabled and is sufficiently blocked to render the cooler inoperable when the current source is disabled. 
   There is also provided a system for electronically controlling a temperature of a device. The system comprises a cooler coupled to receive a current; a temperature monitor to detect a temperature of the device; a temperature detector to produce a signal representative of the device temperature; a cooler driver to determine an amount of current to be received by the cooler in response to the signal; a temperature controller, including at least one current source, each current source further coupled to at least one inductor, to supply the determined amount of current if the device temperature is within a predetermined temperature range and to sufficiently block current to the cooler to render the cooler inoperable if the device temperature is outside the predetermined temperature range. The current source is a monolithic step down regulator. 
   Additional features and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the claims. The features and advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings: 
       FIG. 1  is a block diagram of a system for electronically controlling the temperature of a device consistent with the invention. 
       FIG. 2  is a circuit diagram illustrating features of elements shown in FIG.  1 . 
     FIG.  3 ( a ) is an exploded view of a module for electronically controlling the temperature of a device consistent with the invention. 
     FIG.  3 ( b ) is another view of the module for electronically controlling the temperature of a device shown in FIG.  3 ( a ). 
       FIG. 4  is a flowchart illustrating a method for electronically controlling the temperature of a device consistent with the invention. 
   

   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
   DETAILED DESCRIPTION 
   Referring now to the drawings, in which the same reference numbers will be used throughout the drawings to refer to the same or like parts,  FIG. 1  is a block diagram of a system  100  for electronically controlling the temperature of a device. System  100  may include a device  102 , for example a 980 nm pump laser diode, a thermistor  104 , to monitor and detect the temperature of device  102 , and a cooler  106 , to provide heat transfer away from device  102 . System  100  may also include a cooler driver  108 , to determine an amount of driving current to be supplied to cooler  106 , and a temperature detector  110 , to detect and produce a signal in accordance with and as a function of the temperature of device  102 . System  100  may also include a temperature controller  112 , which allows current to be supplied to cooler  106  or sufficiently blocks current to cooler  106  to render cooler  106  inoperable. System  100  may further include a connection  116 , which provides a connection to cooler driver  108  to form a closed loop feedback section between cooler  106 , cooler driver  108 , and temperature controller  112 . Further, temperature controller  112  may include low heat dissipation inductors and current sources  114 . 
   In the operation of system  100 , thermistor  104  monitors and detects the temperature of device  102 . Thermistor  104  includes a variable resistance that varies as a function of temperature. The variation in resistance is used to vary a voltage that represents the temperature of device  102 . This function of monitoring the temperature can also be performed and implemented by other devices such as a semiconductor-type sensor that varies a voltage as a function of temperature. Thermistor  104  is coupled to detector  110 , so that detector  110  can detect the temperature of device  102  and produce a signal representative of the temperature of device  102 . The signal output of detector  110  is provided to cooler driver  108 , which supplies current to cooler  106 , through temperature controller  112 , for operation of cooler  106  to transfer heat away from device  102 . Cooler  106  can, for example, be a thermoelectric cooler (TEC) with a maximum required current of 1.40 A. When system  100  is implemented with a TEC having the maximum required current of 1.40 A, cooler driver  108  and cooler  106  can be designed to maintain the temperature of device  102  at a near constant temperature of +25° C.+/−1° C. The temperature value and tolerance can also be user defined values that can be adjusted in cooler driver  108 . 
   Temperature controller  112  receives the temperature signal output by detector  110  through cooler driver  108  and compares the temperature with a predetermined temperature range. The predetermined temperature range is selected so that system  100  operates within a predetermined specified limit. Responsive to the temperature signal, temperature controller  112  allows or reduces or blocks current from being supplied to cooler  106 . Current is reduced or blocked from being supplied to cooler  106  to prevent damage to cooler  106  resulting from, for example, excessive drive current to cooler  106  to compensate for a high device temperature. Further, separate circuitry, not shown in  FIG. 1 , may be provided to protect device  102  from damage due to excessive temperature. Normally, current to cooler  106  is reduced or blocked when the temperature of device  102  exceeds an upper limit of the predetermined range, for example 50° C. However, in accordance with alternative designs and circumstances, it may be appropriate to shut down system  100  in the event the temperature drops below a lower limit of the predetermined temperature range, for example 0° C. Thus, temperature controller  112  can serve as a protective thermal shutdown circuit. The selection of the predetermined temperature range depends upon the particular operational characteristics and specifications of device  102  and cooler  106 . For example, if device  102  is a 980 nm pump laser, the predetermined temperature range can be between 0° C. and 50° C. If the temperature is outside the predetermined temperature range, temperature controller  112  prevents the operation of cooler  106 . Specifically, if the temperature is outside the predetermined temperature range, temperature controller  112  sufficiently reduces or blocks the drive current to cooler  106  to render cooler  106  inoperable. Conversely, if the temperature is within the predetermined temperature range, temperature controller  112  allows the supply of sufficient current for operation of cooler  106 . 
   Temperature controller  112  contains circuitry constructed of components including inductors and current sources  114 , which provide a magnitude of current to cooler  106  depending on a determination by cooler driver  108  indicating a required current magnitude as a function of the temperature of device  102 . If the temperature of device  102  is within the predetermined temperature range, the circuitry of temperature controller  112  is enabled and provides current to cooler  106  in response to and in accordance with the determination made by cooler driver  108 . If the temperature of device  102  is outside the predetermined temperature, the circuitry of temperature controller  112  sufficiently reduces or blocks the current passing to cooler  106  to render cooler  106  inoperable. 
   As previously mentioned, cooler  106  provides heat transfer away from device  102  and is driven by current supplied from temperature controller  112  as determined by cooler driver  108 . Optionally, cooler  106  may also be coupled, using connection  116 , to cooler driver  108  to form a closed loop feedback section to cooler driver  108 . Connection  116  enables a quicker response time by cooler driver  108  and temperature controller  112  to adjust to temperature changes in device  102  and allows for a more compact design. 
     FIG. 2  is a circuit diagram illustrating features of elements shown in FIG.  1 . Referring to  FIG. 2 , detector  110  may include resistors  202 ,  204 ,  206 , and  208 , leads  210  and  212 , a voltage supply connection  214 , a common connection  216 , and an amplifier  218 . Resistors  202  and  204  are connected in series between voltage supply connection  214  and common connection  216  to form a voltage divider circuit. Amplifier  218  may further include power supply connections  220  and  222 , inputs  224  and  226 , and an output  228 . Non-inverting input  224  of amplifier  218  is connected through resistor  206  to a node between resistors  202  and  204 . Inverting input  226  of amplifier  218  is connected to common connection  216  through resistor  208 . Amplifier  218  is used as a non-inverting amplifier with a fixed voltage reference at common connection  216 . Thermistor  104  may be connected between leads  210  and  212  to form a feedback gain section using a variable resistance included as part of thermistor  104 . As the detected temperature varies, the variable resistance varies as well, thereby creating a signal on output  228  that is a function of the detected temperature. 
   Cooler driver  108  may include common connection  216 , resistors  230 ,  232 ,  244 , and  246 , a limiting circuit  233 , leads  248  and  250 , and amplifiers  258  and  260 . Limiting circuit may include common connection  216 , resistors  234 ,  236 ,  238 ,  240 ,  242 , a capacitor  252 , and diodes  254  and  256 . Amplifier  258  may further include supply connections  262  and  264 , inputs  266  and  268 , and an output  270 . Amplifier  260  may include power supply connections  272  and  274 , inputs  276  and  278 , and an output  280 . Resistor  230  is coupled between output  228  of amplifier  218  and inverting input  266  of amplifier  258 . Resistor  232  is coupled to form a feedback section between output  270  and input  266 . Non-inverting input  268  of amplifier  258  may be coupled to lead  250 , which can be coupled to a voltage divider circuit of a fixed voltage reference so that a user can define an input voltage to amplifier  258  through input  268 . Resistors  234 ,  236 ,  238 , and  242  are connected, in series, between output  270  of amplifier  258  and inverting input  278  of amplifier  260 . Diode  256  is coupled between common connection  216  and a node between resistors  234  and  236 . Diode  254  is coupled between common connection  216  and a node between resistors  236  and  238 . Capacitor  252  is coupled in parallel with resistor  240  between common connection  216  and a node between resistors  232  and  242 . Non-inverting input  276  of amplifier  260  is coupled to common  216 , through resistor  246 . Further, lead  248  is coupled to input  276 . Resistor  244  is coupled between inverting input  278  and output  280  of amplifier  260 . 
   Temperature controller  112  may include resistors  282 ,  284 ,  286 ,  288 ,  290 ,  292 , and  294 , leads  296 ,  298 , and  300 , capacitors  302 ,  304 ,  306 ,  308 ,  310 ,  314 ,  316 ,  320 ,  322 , inductors  324  and  326 , an amplifier  328 , and current sources  330  and  332 . Amplifier  328  further includes supply connections  334  and  336 , inputs  338  and  340 , and an output  342 . Current source  330  may include inputs  344 ,  346 ,  348 , and an output  358 . Current source  332  may include inputs  360 ,  362 ,  364 , and an output  374 . Resistor  282  is coupled to output  270  of amplifier  258  and in series with resistor  286 . Resistor  286  is further coupled to non-inverting input  338  of amplifier  328 . Resistor  284  is connected at a node between resistors  282  and  286 , and capacitor  302  is connected to non-inverting input  338 . Resistor  284  and capacitor  302  are further connected to common connection  216 . Inverting input  340  of amplifier  328  is connected to common connection  216  through resistor  288 . Resistor  290  is connected between input  340  and output  342  of amplifier  328 , forming a feedback section. Resistor  294  is connected in series between output  342  and lead  296 . Resistor  292  is connected at a node between output  342  and resistor  294 . Capacitor  304  is connected to lead  296 . Resistor  292  and capacitor  304  are further coupled to common connection  216 . Current sources  330  and  332  can be monolithic step-down regulators of a type known in the art. For example, if monolithic step down regulators are used current sources  330  and  332 , inputs  344  and  360  represent an enable (or RUN) connection, inputs  346  and  362  represent a feedback voltage connection (VFB), and inputs  348  and  364  represent an input voltage connection (VIN). Inputs  344  and  360  are further connected to lead  296 . Inputs  346  and  362  are connected to output  280  of amplifier  260 . Inputs  348  and  364  are connected to common connection  216  through capacitors  314  and  316 , respectively, and are input voltage connections to current sources  330  and  332 . Outputs  358  and  374  are coupled to inductors  324  and  326 , respectively. Inductor  324  is further connected to inductor  326 . Capacitors  306 ,  308 ,  310 ,  320 , and  322  are connected in parallel at a node between inductors  324  and  326 . Capacitors  306 ,  308 ,  310 ,  320 , and  322  are further coupled to common connection  216 . Lead  298  is connected at a node between inductors  324  and  326 . 
   In the operation of system  100 , detector  110  monitors and detects the temperature of device  102  and produces a signal that is a function of the detected temperature. Specifically, thermistor  104  is coupled to amplifier  218  to form a feedback gain section, for example by connecting thermistor  104  between leads  210  and  212 . The variable resistance of thermistor  104  changes in a predictable manner to allow amplifier  218  to produce a signal on output  228  that is a scaled voltage based on the variable resistance. Resistors  202 ,  204 ,  206 , and  208  can be selected by the user in order to create a signal on output  228  that is representative of detected temperature and will comply with operational specifications of system  100 . Also, common connection  216  can be connected to amplifier  218  in the manner shown by FIG.  2 . Common connection  216  can be ground (0V). Amplifier  218  can be semiconductor operational amplifier as understood by those skilled in the art. For example, in order to produce a signal on output  228  representative of the detected temperature using supply connection  220  as 5V and supply connection  222  as −2V, resistor  202  can be 20 KΩ, resistor  204  can be 3 KΩ, resistor  206  can be 10 KΩ, and resistor  208  can be 470Ω. 
   Cooler driver  108 , in conjunction with temperature controller  112 , provides an adjustable current in order to drive cooler  106  in response to the temperature of device  102 . If it is desired to lower the temperature of device  102 , an amount of current corresponding to that amount of cooling will be supplied to cooler  106 . Output  228  is coupled to input  266  on amplifier  258  of cooler driver  108  in order to provide the signal on output  228 , representative of the detected temperature of device  102 , to cooler driver  108 . Amplifier  258  can be implemented as a difference amplifier. For example, the signal on input  266  may have a scaled voltage based on the variable resistance of thermistor  104 , which is representative of the detected temperature of device  102 . Lead  250  is connectable to a user-defined voltage source to enable the user to scale the output of amplifier  270  according to the desired application. Lead  250  can be coupled to a voltage divider circuit which derives its source voltage from a fixed voltage reference. For ordinary applications, lead  250  can be coupled to a fixed voltage reference. Therefore, if the difference between input  266  and input  268 , coupled to lead  250 , is large, then there will be a corresponding increase in the driving current supplied to cooler  106 . If there is a small variation in the difference voltage, then the corresponding value for the drive current supplied to cooler  106  will be small. Thus, on output  270  of amplifier  258  there may be a signal representative of the temperature of device  102  that may be at a corresponding level to drive cooler  106 , i.e., a signal value that varies as a function of the temperature of device  102  sufficient to drive cooler  106  at an appropriate level. Operating cooler driver  108  as a function of the difference between two voltages, e.g., the difference between the voltage representative of the temperature of device  102  and voltage representative of lead  250 , rather than a single control voltage, allows for better rejection of voltage fluctuations and random elevated noise levels from extraneous offset values. 
   To further reject noise and voltage fluctuations, amplifier  258  is coupled to limiting circuit  233 . Limiting circuit  233  serves to filter out undesirable voltage fluctuations to amplifier  260 , so that the fluctuations do not damage amplifier  260  or cooler  106 . Limiting circuit  233  may use Schottky diodes for diodes  254  and  256 . For example, to limit voltages outside the range of 0V to 1.3V, resistors  234  and  236  can be 3 KΩ, resistor  238  can be 10 KΩ, resistor  240  can be 4.7 KΩ, and resistor  242  can be 51 KΩ, diodes  256  and  258  can be 30V Schottky diodes with a 1.22 voltage reference, and capacitor  252  can be 0.33 μF. 
   Limiting circuit  233  is coupled to inverting input  278  of amplifier  260 . Therefore, amplifier  258  outputs a signal on output  270  that is received by amplifier  260  after being filtered for voltage fluctuations and noise. The signal received by amplifier  260  determines the amount of current that should be supplied to cooler  106 . Cooler  106  can be connected between lead  248  of cooler driver  108  and lead  298  of temperature controller  112 . This will create a closed loop feedback section, between cooler driver  108  and temperature  112 , using cooler  106 . The signal fed back to cooler driver  108  is a voltage feedback signal that uses cooler  106  as a resistive load. To maintain the temperature at a near constant 25° C.+/−.1° C., while connecting power supply connections  264  and  272  to 5V and connecting power supply connections  262  and  274  to −1.2V, resistor  230  can be 10 KΩ, resistor  232  can be 39K, resistor  244  can be 300 KΩ, and resistor  246  can be 0.2. 
   Temperature controller  112  functions to block or reduce the current supplied to cooler  106  if the detected temperature is outside of the predetermined temperature range. Temperature controller  112  renders the cooler inoperable if the temperature of device  102  is outside of the predetermined temperature range. The extent of the predetermined temperature range may be determined by operational specifications of device  102  or cooler  106  (e.g., for a 980 nm pump laser, the predetermined temperature range can be 0° C.-50° C.). Also, one of ordinary skill in the art may now appreciate that in alternative designs, temperature controller can be coupled to shutdown not only cooler  106 , but also system  100  if the temperature of device  102  is outside the predetermined temperature range. 
   As previously described, output  270  of amplifier  258  is coupled to temperature controller  112  through amplifier  328 . Amplifier  328  can be a comparator, wherein the signal on its input  338  received from output  270  of amplifier  258  is compared against the predetermined temperature range. The predetermined temperature range can be selected by a user so that the current driving cooler  106  is reduced or blocked to render cooler  106  inoperable in the event the temperature of device  102  is outside the predetermined temperature. To implement amplifier  328 , various resistance values and capacitor values can be selected by the user to represent the predetermined temperature range. For example, for a predetermined temperature range of 0° C.-50° C., such as may be suitable for a 980 nm pump laser, power supply connection  334  can be connected to 5V and power supply connection  336  can be connected to common connection  216 , resistor  282  can be 1 MΩ, resistor  284  can be 100 KΩ, resistor  286  can be 5.6 MΩ, resistor  288  can be 8.2 KΩ, resistor  290  can be 100 KΩ, resistor  292  can be 51 KΩ, resistor  294  can be 300 KΩ, capacitor  302  can be 10 μF, capacitor  304  can be 1.0 μF, and supply connection  334  can be 5V. 
   One purpose of amplifier  328  is to output a signal on output  342  which indicates whether current should be supplied to cooler  106  or whether current should be reduced or blocked to render cooler  106  inoperable. Lead  296  is connected to output  342  for this purpose. Lead  296  is also coupled to current sources  330  and  332  to enable current sources  330  and  332  if the temperature of device  102  is within the predetermined temperature range or disable current sources  330  and  332  when the temperature of device  102  is outside the predetermined temperature range. When enabled, current sources  330  and  332  can allow current to pass to cooler  106 . However, when disabled, current sources  330  and  332  reduce or block current to drive cooler  106 , rendering cooler  106  inoperable. If current is to be supplied to cooler  106 , the amount of current is determined by amplifier  260 , as previously described. Inputs  348  and  364  of current sources  330  and  332 , respectively, are voltage inputs which can be supplied by the user through lead  300 . This supplied value can be a fixed reference of 0V. Inductors  324  and  326  are coupled to lead  298  which may be connected to a positive input of cooler  106 . Lead  298  may also be connected to the parallel combination of capacitors  306 ,  308 ,  310 ,  320 , and  322  all having the value of 10 μF. 
   Current sources  330  and  332  can be current sources assembled in a parallel configuration to supply a cooling element, such as cooler  106 , with an appropriate amount of DC current. The appropriate amount of DC current may be controlled by amplifier  260 , as previously described. Current sources  330  and  332  may contain monolithic synchronous step-down switching regulators each capable of supplying 700 mA. The internal synchronous switches of current sources  330  and  332  increase efficiency and eliminate the need for large components dissipating a large amount of power. For example, the use of internal synchronous switches can obviate the need for power transistors. Power transistors dissipate a large amount of power and their use leads to a larger, more costly circuit than using current sources  330  and  332 . Also, current sources  330  and  332  can incorporate a constant frequency, current mode step-down architecture. The values of inductors  324  and  326  are selected so that the current from current sources  330  and  332  remains continuous during burst periods at low load currents. 
   Current sources  330  and  332  are optimized for high efficiency at low load currents. This enables current sources  330  and  332  to maintain better than 90% efficiency over their lifetime. When current sources  330  and  332  are operating normally, efficiency increases as load current increases. Nominal efficiencies can range from 60% at 1 mA to approximately 90% at 700 mA output current. Because each current source may operate from a 0.8 volt reference and incorporates a near 100% duty cycle internal oscillator, it can also provide low dropout voltage operation. Such operation also serves to improve efficiency and thereby lowers power consumption requirements. 
   FIG.  3 ( a ) is an exploded view of a module  350  for electronically controlling the temperature of a device. Module  350  includes a circuit board  352 , a resin layer  354 , and a housing  356 . Board  352  may be an implemented version of cooler driver  108 , detector  110 , and temperature controller  112  of system  100  that can be interconnected on a printed circuit board as typically used in the art. Board  352  may also include pin sets  358  and  360 , which may be hardware equivalents to leads  210 ,  212 ,  248 ,  250 ,  296 ,  298 ,  300  as well as common connection  216  and connections to +5V, +1.2V, and −1.2V voltage supplies. 
   Board  352  can be placed into housing  356 , with resin  354  introduced into housing  356  to cover and encapsulate the components on board  352 . Resin  354  can be a type of semiconductor packaging resin typically found in the art, which is introduced and hardens to protect board  352  within housing  356 . The result is the view of module  350  as shown in FIG.  3 ( b ) which is the result of mounting,board  352  within housing  356  and introducing resin  354 . As also shown in FIG.  3 ( b ), pin sets  358  and  360  protrude from resin  354  and housing  356 . Pin sets  358  and  360  can be used to insert system  350  into a printed circuit board for electronically cooling a semiconductor device. Housing  356  may have dimensions of 1.4 inches by 1.4 inches and a height of 0.310 inches. Board  352  may have dimensions of 1.250 inches by 1.250 inches and can be attached to housing  356  by means typically used in the art. Pin sets  358  and  360  may extend 0.230 inches from housing  356  and are circuit connections for board  352  to other circuit components. Module  350  may be implemented with smaller dimensions of housing  356 , e.g., 1 inch by 1 inch with a height of 0.2 inches. 
   Using current sources  330  and  332  with inductors  324  and  326  results in less heat being generated by the operation of cooler driver  108 , detector  110 , and temperature controller  112  than by conventional use of power transistors. Due to the low heat generation, integrating cooler driver  108 , detector  110 , and temperature controller  112  into a single, compact module, such as module  350 , is possible. 
     FIG. 4  is a flowchart  400  of a method for electronically controlling the temperature of a device. The method for electronically controlling the temperature of a device begins at stage  402 , where a current is supplied to a temperature regulating element. The current is supplied using low heat dissipation current sources that work in conjunction with low heat dissipation inductors. The current may be variable depending upon the temperature of the device. The temperature of the device is determined at stage  404  using a sensor that varies a voltage as a function of temperature, such as a thermistor. At stage  406 , the temperature of the device is compared against a predetermined temperature range, e.g., a desired operating range selected by the user. Two outcomes may arise from stage  406 . At stage  408 , the current is sufficiently blocked from the temperature regulating element if the temperature of the device is outside the predetermined temperature range. Operating the temperature regulating element when the temperature of the device is outside the predetermined temperature range may cause damage to the temperature regulating element because of excessive drive current. If the temperature of the device is within the predetermined temperature range, the current sources and inductors continue to provide current to the temperature regulating element, with the amount of current being controlled according to the detected temperature of the device. 
   Although  FIGS. 1-4  mainly illustrate electronically controlling the temperature of device through the use of coolers, it will now be appreciated by those in the art that the above teaching can also be applied to heating elements or any other element that may be used to regulate temperature. 
   Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the claims disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.

Technology Classification (CPC): 6