Patent Publication Number: US-9432019-B2

Title: Control chip and system using the same for power saving

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a power control chip, in particular to a control chip and a system using the same for power saving. 
     2. Description of Related Art 
     As technology rapidly develops, people&#39;s dependence on using electronic apparatuses, such as air-conditioners, refrigerators, computers, washers, and the like, in their daily life increases. Electronic apparatuses however cannot operate without “power”, and the issue of power saving thus arose. As more and more electronic apparatuses are being used nowadays, the issue of power saving becomes an important issue that needs to be addressed. Thus, “low power” has become the subject of future research for most industries and the demands or requirements for power saving also become strict. 
     Please refer to  FIG. 1 , which shows a diagram of a conventional power saving control system. For example, a conventional power saving control system  1  for a monitor includes a first-order LDO regulator  11 , a second-order LDO regulator  12 , and a control chip  13 . The control chip  13  includes a microcontroller  131 . The second-order LDO regulator  12  is coupled to the first-order LDO regulator  11 . The first-order LDO regulator  11  and the second-order LDO regulator  12  are coupled to the control chip  13 , respectively. 
     Generally, the conventional monitor operatively receives an input voltage VI (e.g., 12V/14V/19V), converts the input voltage VI received into a first voltage V 1  (e.g., 5V) with the first-order LDO regulator  11 , and converts the first voltage V 1  received into a second voltage V 2  (e.g., 3.3V) with the second-order LDO regulator  12 . The first voltage V 1  and the second voltage V 2  are respectively supplied to power the control unit  13  thereafter. However, in practice, the first voltage V 1  and the second voltage V 2  not only are supplied to power the control unit  13 , but also used to power other external components that are coupling to the second-order LDO regulator  12  and the first-order LDO regulator  11 . 
     Conventionally, the control chip  13  is unable to directly disconnect itself from receiving the driving voltage (i.e., the voltages supplied by the first-order LDO regulator  11  and the second-order LDO regulator  12 ) even when the conventional monitor is operated under a power saving mode, and the control chip  13  instead is operated in a low-power standby state. Therefore, the external components coupling to the second-order LDO regulator  12  and the first-order LDO regulator  11  would continue to consume the power as the first-order LDO regulator  11  and the second-order LDO regulator  12  cannot be stopped. In other words, the external components would continually receive the first and second voltages and consume power even when the control chip  13  is completely powered down. 
     SUMMARY 
     An exemplary embodiment of the present disclosure provides a control chip for power saving. The control chip is configured to operatively receive a first voltage and a first bias voltage. The control chip includes a microcontroller unit and a low power module. The low power module is coupled to the microcontroller unit. The microcontroller unit receives the first voltage for controlling the operation of at least one component under an operating mode and stops receiving the first voltage under a power saving mode. The low power module operatively receives the first bias voltage. When the microcontroller unit switches from the operating mode to the power saving mode, the low power module operatively generates a first control signal to cause the microcontroller unit to stop receiving the first voltage. When the low power module detects a trigger signal, the low power module operatively generates a second control signal to cause the microcontroller unit to continue receiving the first voltage. 
     An exemplary embodiment of the present disclosure provides a control system for power saving. The control system includes a switching regulator, an external voltage biasing circuit, and a control chip. The control chip includes a microcontroller unit and a low power module. The control chip is coupled to the switching regulator and the external voltage biasing circuit. The low power module is coupled to the microcontroller unit. The switching regulator supplies a first voltage. The external voltage biasing circuit operatively supplies a first bias voltage. The microcontroller unit operatively receives a first voltage for controlling the operation of at least one component under an operating mode and stops receiving the first voltage under a power saving mode. The low power module receives the first bias voltage. When the microcontroller unit switches from the operating mode to the power saving mode, the low power module operatively generates a first control signal to cause the microcontroller unit to stop receiving the first voltage. When the low power module detects a trigger signal, the low power module operatively generates a second control signal to cause the microcontroller unit to continue receiving the first voltage. 
     To sum up, the control chip and the control system provided by exemplary embodiments of the present disclosure are operable to achieve power saving for an electronic apparatus. More specifically, in order for a conventional control system to keep the microcontroller unit operating in the power saving mode, the conventional control system must continuously receive power, and the voltage regulator for supplying power to the microcontroller unit and other components coupling thereto has to continue to operate and consume power, which is a waste of power. Thus, an exemplary embodiment of the present disclosure replaces the conventional used microcontroller unit with a control chip having a low power module integrated therein and the control chip is operable to detect and determine the waking-up operation of the electronic apparatus using simple digital circuitries, and operable to directly turn off the microcontroller unit and the voltage regulator, thereby effectively achieve power saving effect. 
     In order to further understand the techniques, means and effects of the present disclosure, the following detailed descriptions and appended drawings are hereby referred to, such that, and through which, the purposes, features and aspects of the present disclosure can be thoroughly and concretely appreciated, however, the appended drawings are merely provided for reference and illustration, without any intention that they be used for limiting the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. 
         FIG. 1  is a diagram of a conventional control system for power saving. 
         FIG. 2  is a diagram of a control system for power saving provided according to an exemplary embodiment of the present disclosure. 
         FIG. 3  is a diagram of a control system for power saving provided according to another exemplary embodiment of the present disclosure; 
         FIG. 4  is a diagram of a low power module provided according to an exemplary embodiment of the present disclosure; 
         FIG. 5  is a diagram illustrating a counting operation of a determining unit provided according to an exemplary embodiment of the present disclosure. 
         FIG. 6  is a diagram of a low power module provided according to another exemplary embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. However, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the accompanying drawings, the relative thickness of layers and regions may be exaggerated for clarity. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Exemplary embodiments of the present disclosure provide a control chip and a control system for power saving. The control chip and the control system are operable to resolve the issue of the electronic apparatus wasting power under a power saving mode thereof by preventing the electronic apparatus from consuming power supplied by the LDO regulator even under the power saving mode. The exemplary embodiment of the present disclosure replaces the original microcontroller unit with a control chip having a low power module integrated therein and the control chip is operable to automatically detect and determine the waking-up operation of the electronic apparatus, and correspondingly control the on/off operation of the switching regulator, thereby effectively achieve the objective of power saving. Although the following exemplary embodiments are illustrated with a display or a monitor, persons skilled in the art should understand that the concepts disclosed by embodiments of the present disclosure are also applicable to any electronic apparatus having the power saving mode. The present disclosure is not limited thereto. The control chip and the control system for power saving are illustrated in detail in the following paragraphs. 
     Please refer to  FIG. 2 , which shows a diagram illustrating a control system for power saving provided according to an exemplary embodiment of the present disclosure. A control system  2  for power saving includes a switching regulator  21 , an external voltage biasing circuit  22 , and a control chip  23 . The control chip  23  further includes a microcontroller unit  231  and a low power module  232 . The switching regulator  21  and the external voltage biasing circuit  22  are coupled to the control chip  23 . The low power module  232  is coupled to the microcontroller unit  231 . 
     The switching regulator  21  is configured to operatively convert an input voltage VI (e.g., 12V/14V/19V) received and generate the first voltage V 1  (e.g., 5V) and the second voltage V 2  (e.g., 3.3V) for supplying necessary power to the control unit  23  and other external components coupling thereto. In the instant embodiment of the present disclosure, the switching regulator  21  is implemented with a switch voltage regulator. In other embodiments, the switching regular  21  may be implemented with a linear series regulator or the equivalents. Thus, the present disclosure does not limit the exact type or implementation of the switching regulator  21 . 
     The external voltage biasing circuit  22  is operable to supply a first external voltage VB to the low power module  232  of the control chip  23 . In the instant embodiment of the present disclosure, the control system  2  for power saving has the external voltage biasing circuit  22  disposed between a voltage source for generating the input voltage V 1  and the control chip  23 . The external voltage biasing circuit  22  generates the first external voltage VB by voltage division. In the instant embodiment of the present disclosure, the external voltage biasing circuit  22  is implemented by a fixed-value resistor and generates a voltage same as the second voltage V 2 . However, the external voltage biasing circuit  22  can also be implemented with an adjustable or tunable resistor, which can be adjusted by an operator based on the operational needs, and the present disclosure is not limited thereto. It shall be noted that the configuration of the external voltage biasing circuit  22  in the instant embodiment is able to operatively provide an input current of less than 10 μA to the control chip  23 . 
     The control chip  23  is configured to operatively control the operation of at least one circuit component coupling thereto. In the instant embodiment of the present disclosure, the control chip  23  is configured to have an operating mode and a power saving mode. However, in another embodiment, the power saving mode may be set as a sleep mode or any other equivalent mode. Specifically, the operating mode is the working or active state of the control chip  23 . The power saving mode is the standby state or speed reduction state of the control chip  23 . Under the operating mode, the control chip  23  drives the microcontroller unit  231  to control the operation of circuit components (e.g., audio codec, fan, or the like.) coupling thereto upon receiving the first voltage V 1  and the second voltage V 2 . The control chip  23  stops to receive the first voltage V 1  under the power saving mode. Moreover, the control chip  23  operatively receives the first bias voltage VB and drives the low power module  232  to detect a trigger signal TES. In the instant embodiment of the present disclosure, the microcontroller unit  231  is implemented with an 8051-based microcontroller. However, those skilled in the art should understand that the microcontroller unit  231  can be implemented based on the operational requirement of the electronic apparatus, and the present disclosure does not limit the exact type and the exact implementation used for the microcontroller unit  231 . It is worth noting that since the switching regulator  21  is shutdown or turned off under the power saving mode, circuit components that receive the first voltage V 1  and the second voltage V 2  thus will not consume power, the present disclosure therefore achieves the objective of power saving for electronic apparatus. 
     In detail, when the microcontroller unit  231  has switched from the power saving mode to the operating mode, the low power module  232  operatively outputs a control signal CS to turn off the switching regulator  21  to stop the microcontroller unit  231  from receiving the first voltage V 1  and the second voltage V 2 . The low power module  232  outputs the control signal CS to turn on the switching regulator  21  to cause the microcontroller unit  231  to continue receiving the first voltage V 1  and second voltage V 2  upon detecting the trigger signal TES In other words, the control signal CS outputted by the low power module  232  is configured to selectively turn on or turn off the switching regulator  21 . The control signal CS is generated responsive to the trigger signal TES to cause the microcontroller unit  231  to continue receiving the first voltage V 1  and second voltage V 2 . However, it shall be noted that the low power module  232  in the instant embodiment receives the first bias voltage VB under either the operating mode or the power saving mode for constantly detecting the trigger signal TES. 
     Please refer to  FIG. 3 , which shows a diagram illustrating a control system for power saving provided according to another exemplary embodiment of the present disclosure. In the instant embodiment, the control system  2 ′ is essentially the same as the control system  2 , and the difference is that a control chip  23 ′ of the control system  2 ′ further includes a switch unit  233 . The switch unit  233  is disposed on the current path formed between the low power module  232  and the external voltage biasing circuit  22  for receiving the first bias voltage VB from the external voltage biasing circuit  22 . The switch unit  233  is controlled by the microcontroller unit  231 . In other words, the switch unit  233  operatively controls the low power module  232  whether or not to receive the first bias voltage VB. In the instant embodiment of the present disclosure, the switch unit  233  can be implemented with a metal oxide semiconductor field effect transistor (MOSFET). More specifically, before the control chip  23 ′ has switched from the operating mode to the power saving mode, the microcontroller unit  231  turns on the switch unit  233  and causes the low power module  232  to receive the first bias voltage VB supplied from the external voltage biasing circuit  22  for the control chip  23 ′ to conduct the low power detection operation. At the meantime, the low power module  232  generates the control signal CS to turn off the switching regulator  21 , and the control chip  23 ′ stops receiving the first voltage V 1  and the second voltage V 2  supplied by the switching regulator  21 . Additionally, after the control chip  23 ′ has switched from the power saving mode to the operating mode, the microcontroller unit  231  turns off the switch unit  233 , and causes the low power module  232  to stop receiving the first bias voltage VB and prevents the low power module  232  from consuming power. 
     The details on the operations of the low power module  232  are illustrated in the following paragraphs. Please refer to  FIG. 4 , which shows a diagram illustrating a low power module provided according to an exemplary embodiment of the present disclosure. The low power module  232  includes a signal detector  2321 , a clock generator  2322 , and a determining unit  2323 . The determining unit  2323  is coupled to the signal detector  2321  and the clock generator  2322 . 
     The signal detector  2321  comprises of necessary circuitries, logics and/or codes for operatively detecting the trigger signal TES. More specifically, the signal detector  2321  is configured to detect a change in the logic level of the trigger signal TES, i.e., detects the level transition from high logic level to low logic level or from low logic level to high logic level. 
     The clock generator  2322  including comprises of necessary logics, circuitries, and/or codes for operatively generating a clock signal TS. In the instant embodiment of the present disclosure, the clock generator  2322  can be implemented with an embedded oscillator that can generate a 2 KHz clock signal TS with a positive feedback digital circuit and a sixth order distributed first-in-first-out circuit. In practice, the clock generator  2322  also can be implemented with an oscillator formed of other circuitry elements for generating clock signals TS at different frequency based on practical operational needs or users&#39; requirement, and the present disclosure is not limited thereto. 
     The determining unit  2323  comprises of necessary logics, circuitries, and/or codes such that the determining unit  2323  operatively starts counting the trigger signal TES according to the clock signal TS received from the clock generator  2322  when the signal detector  2321  detects a logic level change in the trigger signal TES. Moreover, the determining unit  2323  generates the control signal CS after counting the trigger signal TES for a time interval. That is, the determining unit  2323  starts counting the trigger signal TES when the signal detector  2321  detects the trigger signal TES under the power saving mode and generates the control signal CS after an elapse of the time interval. Please refer to  FIG. 5  in conjunction with  FIG. 4 , which shows a diagram illustrating a counting operation of a determining unit provided according to the exemplary embodiment of the present disclosure. When the signal detector  2321  detects the trigger signal TES changed from a voltage level S 1  to a voltage level S 2 , the determining unit  2323  starts counting. The determining unit  2323  operatively generates the control signal CS after the counting time reaching the time interval T 1 ˜T 2  (e.g., 4 ms in  FIG. 5 ). It is worth to note that the time interval may be configured and preset by the manufacturer, and the present disclosure is not limited thereto. 
     Next, please refer to  FIG. 6  in conjunction with  FIG. 2 , which shows a diagram illustrating a low power module provided according to another exemplary embodiment of the present disclosure. The difference between a low power module  332  in  FIG. 6  and the low power module  232  in  FIG. 2  is in that the low power module  332  has multiple signal detectors including a function key detection unit  3321 - 1 , a power key detection unit  3321 - 2 , and a cable detection unit  3321 - 3  as shown In  FIG. 6 . 
     In the instant embodiment, the function key detection unit  3321 - 1  is configured to detect the functional keys of the monitor such as “MENU”, “UP”, “DOWN”, “LEFT”, and “RIGHT” under the power saving mode. The function key detection unit  3321 - 1  herein is a 32-level decoder, and is configured to assist the determining unit  3323  in identifying which functional key has pressed by user. Similarly, the determining unit  3323  starts counting according to the clock signal TS generated by the clock generator  3322  when the function key detection unit  3321 - 1  detects a change in the logic level of a trigger signal TES 1  generated as the user presses one of the functional keys “MENU”, “UP”, “DOWN”, “LEFT”, and “RIGHT”. 
     In the instant embodiment, the power key detection unit  3321 - 2  is configured to detect a power key of the monitor under power saving mode. Similar to the signal detector  2321  of the embodiment in  FIGS. 3-4 , the power key detection unit  3321 - 2  operatively detects the change in the logic level of a trigger signal TES 2  generated as the user presses down the power key. Similarly, the determining unit  3323  starts counting according to the clock signal TS generated by the clock generator  3322  when the power key detection unit  3321 - 2  detects a change in the logic level of a trigger signal TES 2 . 
     The cable detection unit  3321 - 3  is configured to detect when a cable is connected to or disconnect from the monitor under the power saving mode. More specifically, when the cable connects to the general purpose input/output of the monitor, the determining unit  3323  starts counting according to the clock signal TS generated by the clock generator  3322  when the cable detection unit  3321 - 3  detects a change in the logic level of a trigger signal TES 3 . 
     The determining unit  3323  operatively starts counting upon receiving any one of the trigger signals TES 1 -TES 3  and generates the control signal CS to turn on switching regulator  21  after counted the time interval, and causes the microcontroller unit  231  to continue receiving the first voltage V 1  and the second voltage V 2  supplied by the switching regulator  21 . 
     It is worth noting that the determining unit  3323  further is operable to generate light signals corresponding to different trigger signal TES 1 -TES 3  for controlling display lights (not shown) to show the current operating mode or state for the monitor. 
     To sum up, the control chip and the control system provided by exemplary embodiments of the present disclosure are operable to achieve power saving for an electronic apparatus. More specifically, in order for a conventional control system to keep the microcontroller unit operating in the power saving mode, the conventional control system must continuously receive power and the voltage regulator for supplying power to the microcontroller unit and other components coupling thereto has to continue to operate and consume power, which is a waste of power. Thus, the exemplary embodiment of the present disclosure replaces the conventionally used microcontroller unit with a control chip having a low power module integrated therein and the control chip is operable to detect and determine the waking-up operation of the electronic apparatus using simple digital circuitries, and operable to directly turn off the microcontroller unit and the voltage regulator, thereby effectively achieve power saving effect. It is worth noting that the low power module of the present disclosure can control the total current received by the control chip to be lower than 10 μA while the control system is operated under the power saving mode. 
     The above-mentioned descriptions represent merely the exemplary embodiment of the present disclosure, without any intention to limit the scope of the present disclosure thereto. Various equivalent changes, alternations or modifications based on the claims of present disclosure are all consequently viewed as being embraced by the scope of the present disclosure.