This disclosure relates to a voltage regulator and a control method thereof.
The power management system for the conventional processor (such as the processors inside smart phones or cars) usually has a set of low dropout (LDO) regulators to dynamically adjust voltages. Generally, the LDO regulator is primarily embodied by the analog control technology or the sync digital control technology.
If the LDO regulator is embodied by the analog control technology, the reaction speed of the LDO regulator actively adjusting the voltage is limited by the bandwidth related with the analog control circuit, so the speed of adjusting the voltage cannot be increased effectively. Furthermore, when the LDP regulator operates in the static state, since the LDO regulator still needs to provide the bias current to maintain its operation, the static work current for the analog control circuit cannot be decreased during the static state.
If the LDO regulator is embodied by the sync digital control technology, the reaction speed of the LDO regulator dynamically adjusting the voltage is limited by the clock rate of the clock frequency signal for the digital control circuit. In order to increase the reaction speed of the LDO regulator actively adjusting the voltage, the clock rate of the clock frequency signal has to be increased. However, increasing the clock rate of the clock frequency signal will increase the current waste of the digital control circuit and also cause the occurrence of inrush current.
According to one or more embodiments, the disclosure provides a voltage regulator adapted to dynamically adjust an output voltage from a first output end of the voltage regulator. In one embodiment, the voltage regulator comprises a plurality of switching transistors and a control circuit. Each switching transistor has a first end for receiving a driving voltage, a second end electrically connected with the first output end, and a control end. The switching transistors adjust the output voltage. The control circuit comprises an input end for receiving a reference voltage, a feedback end for receiving the output voltage, and a plurality of second output ends electrically connected with the control ends of the switching transistors respectively. The control circuit compares the output voltage with the reference voltage, and selectively turns on or off the switching transistors according to the comparison between the output voltage and the reference voltage whereby the output voltage approaches the reference voltage.
According to one or more embodiments, the disclosure also provides a control method of a voltage regulator, which is adapted to dynamically adjust an output voltage outputted by the voltage regulator which comprises a plurality of switching transistors and a control circuit, and each switching transistor has a first end for receiving a driving voltage, a second end electrically connected with an end outputting the output voltage, and a control end electrically connected with the control circuit. In one embodiment, the control method comprises the following steps. First, an output voltage is fed back to a control circuit. Secondly, the output voltage is compared with a reference voltage. Lastly, the switch transistors are selectively turned on or off according to the comparison between the output voltage and the reference voltage, whereby the output voltage approaches the reference voltage.
The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the disclosure, and wherein:
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
The disclosure provides a voltage regulator according to one or more embodiments. Referring to
The transistor array 12 comprises a plurality of switching transistors M_1 to M_n, wherein n is a positive integer larger or equal to 1. Each of the switching transistors M_1 to M_n has a first end for receiving a driving voltage VDD, a second end electrically connected with the output end (i.e. the nodes supply the output voltage VSUP) of the voltage regulator 1, and a control end. In one embodiment, each of the switching transistors M_1 to M_n may be a metal oxide semiconductor field effect transistor (MOSFET). In this case, the source of the MOSFET may be the first end of the switching transistor, the drain of the MOSFET may be the second end of the switching transistor, and the gate of the MOSFET may be the control end of the switching transistor.
The control circuit 10 comprises an input end IN_1, a feedback end IN_2, and a plurality of output ends (or called second output ends) OUT_1 to OUT_n. The input end IN_1 receives a reference voltage VRF. The feedback end IN_2 receives the output voltage VSUP which is fed back from the output end of the voltage regulator 1. The output ends OUT_1 to OUT_n are electrically connected with the control ends of the switching transistors M_1 to M_n respectively so that the switching transistors M_1 to M_n are able to be controlled by the control circuit 10.
The control circuit 10 is configured to compare the output voltage VSUP with the reference voltage VRF to selectively turn on or off the switching transistors M_1 to M_n so that the output voltage VSUP approaches the reference voltage VRF. Specifically, when the control circuit 10 determines that the output voltage VSUP is smaller than the reference voltage VRF, the control circuit 10 turns on one or more of the switching transistors M_1 to M_n. Herein, since the equivalent resistance value of the transistor array 12 increases, the driving current flowing through the transistor array 12 increases, and then the output voltage VSUP increases until the output voltage VSUP is larger or equal to the reference voltage VRF. On the other hand, when the control circuit 10 determines that the output voltage VSUP is larger than the reference voltage VRF, the control circuit 10 turns off one or more of the switching transistors M_1 to M_n. Herein, since the equivalent resistance value of the transistor array 12 decreases, the driving current flowing through the transistor array 12 decreases, and then the output voltage VSUP decreases until the output voltage VSUP is smaller or equal to the reference voltage VRF. Whenever the output voltage VSUP is smaller than the reference voltage VRF, the control circuit 10 repeats the aforementioned operation. In other words, the switching transistors M_1 to M_n are configured to adjust the output voltage VSUP.
To more clearly illustrate the operation of the control circuit 10, please refer to
Each driving module comprises a first input pin PIN_1, a first output pin PIN_2, a second input pin PIN_3, and a second output pin PIN_4. The first reflecting module 102 comprises a first input pin PIN_1, a first output pin PIN_2, a second input pin PIN_3, and a third input pin PIN_4. The second reflecting module 104 comprises an input pin PIN_1 and an output pin PIN_4. The first output pin PIN_2 of the first reflecting module 102 is connected with the first input pin PIN_1 of the driving module 100_1. The first output pin PIN_2 of the driving module 100—n is connected with the input pin PIN_1 of the second reflecting module 104. The first output pin PIN_2 of the driving module 100_1 is connected with the first input pin PIN_1 of the next stage driving module (i.e. the driving module 100_2. Similarly, the first output pin PIN_2 of the driving module 100_2 is connected with the first input pin PIN_1 of the driving module 100_3. The connection of the first output pins PIN_2 of the rest of the driving modules 100_1 to 100—n can be deduced by analogy. The second input pin PIN_3 and the third input pin PIN_4 of the first reflecting module 102 are connected with the second output pin PIN_4 of the driving module 100_2 and the second output pin PIN_4 of the driving module 100_1 respectively. The output pin PIN_4 of the second reflecting module 104 is connected with the second input pin PIN_3 of the driving module 100—n−1. The second output pin PIN_4 of the driving module 100_3 is connected with the second input pin PIN_3 of the driving module (i.e. the driving module 100_1) before the previous stage driving module (i.e. the driving module 100_2) of the driving module 100_3. Similarly, the second output pin PIN_4 of the driving module 100_4 is connected with the second input pin PIN_3 of the driving module 100_2). The connection of the second output pins PIN_4 of the rest of the driving module 100_1 to 100—n can be deduced by analogy. The second input pin PIN_3 of the driving module 100—n is grounded.
When the first input pin PIN_1 of the Ith stage driving module 100—i in the driving modules 100_1 to 100—n receives a triggering signal, the Ith stage driving module 100—i may selectively turn on or off the switching transistor M_i, which corresponds to the Ith stage driving module 100—i, according to the comparison between the reference voltage VRF and the output voltage VSUP, wherein i is smaller or equal to n, and is a positive integer.
The first reflecting module 102 outputs the triggering signal to the first input pin PIN_1 of the driving module 100_1 (or called the first stage driving module). Moreover, when the first reflecting module 102 receives the triggering signal fed back from the second output pin PIN_4 of the driving module 100_1 or the second output pin PIN_4 of the driving module 100_2 (or called the second stage driving module), the first reflecting module 102 may transfer this triggering signal to the first input pin PIN_1 of the driving module 100_1. The second reflecting module 104, via its first input pin PIN_1, receives the triggering signal sent from the first output pin PIN_2 of the driving module 100—n (or called the last stage driving module), and transfers the triggering signal to the second input pin PIN_3 of the driving module 100—n−1 (or called the second last stage driving module) through the output pin PIN_4 of the second reflecting module 104. In other words, the first reflecting module 102 and the second reflecting module 104 are configured to make sure that the voltage regulator 1 can operate normally during the transition period of the output voltage VSUP.
Referring to
The output end (i.e. Q end) of the SR flip-flop 1002 is coupled to the output end OUT_i of the control circuit 10 and is electrically connected with the control end of the switching transistor M_i. The first delay unit 1006 is electrically connected with the first input pin PIN_1 of the Ith stage driving module 100—i and one of the input ends of the Muller C logic gate 1008. The other input end of the Muller C logic gate 1008 is electrically connected with the second delay unit 1014 and one of the input ends of the AND logic gate 1010. The output end of the Muller C logic gate 1008 is electrically connected with one of the input ends of the OR logic gate 1012. The other input end of the OR logic gate 1012 is electrically connected with the LCK end of the multiplexer 1004. The output end of the OR logic gate 1012 is electrically connected with one end of the second delay unit 1014. The other end of the second delay unit 1014 is electrically connected with one of the input ends of the AND logic gate 1010 and the B end of the multiplexer 1004.
The other input end of the AND logic gate 1010 is electrically connected with the Q end of the SR flip-flop 1002. The output end of the AND logic gate 1010 is electrically connected with the second output pin PIN_4 of the Ith stage driving module 100—i. The second input pin PIN_3 of the Ith stage driving module 100—i is electrically connected with the A end of the multiplexer 1004. The Z end of the multiplexer 1004 is electrically connected with the first output pin PIN_2 of the Ith stage driving module 100—i. The U end, W end, and V end of the multiplexer 1004 are electrically connected with the output end OUT_i, the output end OUT_i+1, and the output end OUT_i+2 of the control circuit 10 respectively. Furthermore, the multiplexer 1004 receives a lock signal LCKB due to which the switching transistor M_i is turned on continuously.
The amplifier 1000 is controlled by the triggering signal received by the first output pin PIN_1 of the Ith stage driving module 100—i to compare the reference voltage VRF with the output voltage VSUP. For example, the amplifier 1000 is an error amplifier or a variable gain amplifier (VGA), but the disclosure is not limited thereto. The first delay unit 1006 and the second delay unit 1014 delay a first time period T1 and a second time period T2 respectively. The detail of the first time period T1 and the second time period T2 will be described in
When the input ends of the Muller C logic gate 1008 receive a low logic signal of ‘0’ at the same time, the output end of the Muller C logic gate 1008 outputs a low logic signal of ‘0’. When the input ends of the Muller C logic gate 1008 receive a high logic signal of ‘1’ at the same time, the output end outputs a high logic signal of ‘1’. When the input ends of the Muller C logic gate 1008 receive a high logic signal of ‘1’ and a low logic signal of ‘0’ respectively at the same time, the output end of the Muller C logic gate 1008 does not change. The multiplexer 1004 may be a path multiplexer (PMUX), and its truth table is shown in Table 1.
Referring to
As shown in
As shown in
In other words, when the Ith stage driving module 100—i determines that the output voltage VSUP is larger than the reference voltage VRF, the Ith stage driving module 100—i feeds the triggering signal back to the second input pin PIN_3 of the (I−2)th stage driving module 100—i−2, and the (I−2)th stage driving module 100—i−2 transfers the triggering signal to the (I−1)th stage driving module 100—i−1. Therefore, the (I−1)th stage driving module 100—i−1 turns off the switching transistor M_i−1, which corresponds to the (I−1)th stage driving module 100—i−1, according to the comparison between the reference voltage VRF and the output voltage VSUP in order to reduce the output voltage VSUP.
Furthermore, after the (I−1)th stage driving module 100—i−1 turns off the switching transistor M_i−1 corresponding to the (I−1)th stage driving module 100—i−1, the (I−1)th stage driving module 100—i−1 feeds the received triggering signal back to the (I−3)th stage driving module 100—i−3, and then the (I−3)th stage driving module 100—i−3 transfers the triggering signal to the (I−2)th stage driving module 100—i−2.
To more clearly illustrate the operation of the driving modules 100_1 to 100—n in
As shown in
When the first output pin PIN_2 of the eighth stage driving module 100_8 provides a triggering signal Req8 to the first input pin PIN_1 of the ninth stage driving module 100_9, the ninth stage driving module 100_9 will know that the output voltage VSUP during the time period between the time points t3 and t4 is still smaller than the reference voltage VRF, and then reduces the voltage level of the output end OUT_9 at the time point t4. Therefore, the switching transistor M_9 is turned on, the output voltage VSUP increases, and the ninth stage driving module 100_9 provides a triggering signal Req9 to the tenth stage driving module 100_10.
When the first input pin PIN_1 of the tenth stage driving module 100_10 receives the triggering signal Req9, the tenth stage driving module 100_10 will know that the output voltage VSUP is larger than the reference voltage VRF during the time period between the time points t4 and t5. Therefore, the tenth stage driving module 100_10 does not change the voltage level of the output end OUT 10 so that the output voltage VSUP is remained. Moreover, the tenth stage driving module 100_10, through the second output pin PIN_4, feeds a triggering signal Brq10 back to the second input pin PIN_3 of the eighth stage driving module 100_8, so that the eighth stage driving module 100_8 transfers the triggering signal Brq10 to the ninth stage driving module 100_9.
When the first input pin PIN_1 of the ninth stage driving module 100_9 receives the triggering signal Brq10 sent by the tenth stage driving module 100_10, the ninth stage driving module 100_9 will know that the output voltage VSUP is larger than the reference voltage VRF during the time period between the time points t5 and t6. Therefore, the ninth stage driving module 100_9 increases the voltage level of the output end OUT_9 at the time point t6 to turn off the switching transistor M_9 to decrease the output voltage VSUP. The ninth stage driving module 100_9, through the second output pin PIN_4, sends the triggering signal Brq9 back to the second input pin PIN_3 of the seventh driving module 100_7, so that the seventh driving module 100_7 further transfers the triggering signal Brq9 to the eighth stage driving module 100_8.
When the first input pin PIN_1 of the eighth stage driving module 100_8 receives the triggering signal Brq9 sent by the ninth stage driving module 100_9, since the switching transistor M_8, which corresponds to the eighth stage driving module 100_8, has been turned on, the eighth stage driving module may directly provide the triggering signal Req8 to the ninth stage driving module 100_9.
When the ninth stage driving module 100_9 receives the triggering signal Req9, the ninth stage driving module 100_9 will know that the output voltage VSUP is smaller than the reference voltage VRF during the time period between the time points t7 and t8. Also, the ninth stage driving module 100_9 decreases the voltage level of the output end OUT_9 at the time point t8 to turn on the switching transistor M_9 to increase the output voltage VSUP. The ninth stage driving module 100_9 then provides the triggering signal Req9 to the tenth stage driving module 100_10.
In this way, since the switching transistor M_9 is continually and alternately turned on and off, the output voltage VSUP of the voltage regulator 1 oscillates based on the reference voltage VRF, as shown in the voltage oscillation area A1 in
Furthermore, when the output voltage VSUP approaches the reference voltage VRF and one of the switching transistors M_1 to M_n continues to be turned on and off, the voltage regulator 1 continues to keep the switching transistor on to stabilize the output voltage VSUP and further reduce the energy for switching the switching transistor changing on and off. For example, in
In the disclosure, there is no limitation on the increase range of the output voltage VSUP when each of the switching transistors M_1 to M_n is turned on. The driving current provided by the Ith driving module 100—i is not related to the driving current provided by the driving module 100—i−1 and the driving current provided by the driving module 100—i+1.
Thereinafter, according to one or more embodiments, the disclosure also provides a control method of the voltage regulator 1 in
Referring to
In step S600, the voltage regulator 1 feeds the output voltage VSUP back to the control circuit 10. Moreover, the voltage regulator 1 provides the reference voltage VRF to the control circuit 10. In step S602, the control circuit 10 compares the output voltage VSUP with the reference voltage VRF. Lastly, in step S604, the control circuit 10 selectively turns the switch transistors M_1 to M_n on or off according to the comparison between the output voltage VSUP and the reference voltage VRF so that the output voltage VSUP approaches the reference voltage VRF.
In the step S602, when the output voltage VSUP is smaller than the reference voltage VRF, the control circuit 10 turns on one or more of the switching transistors M_1 to M_n until the output voltage VSUP is larger than the reference voltage VRF. In contrast, when the output voltage VSUP is larger than the reference voltage VRF, the control circuit 10 turns off one or more of the switching transistors M_1 to M_n until the output voltage VSUP is smaller than the reference voltage VRF.
When the output voltage VSUP approaches the reference voltage VRF and one of the switching transistors M_1 to M_n is continually turned on and off, the control circuit 10 keeps the one of the switching transistors M_1 to M_n on to stabilize the output voltage VSUP.
Referring to
Follow the step S704, in step S708, the control circuit 10 determines whether one of the switching transistors M_1 to M_n is continually turned on and off. If the control circuit 10 determines that one of the switching transistors M_1 to M_n has been turned on and off over a preset number of times, the control circuit 10 keeps this switching transistor on to stabilize the output voltage VSUP as shown in step S710. If the control circuit 10 determines that one of the switching transistors M_1 to M_n has not been turned on and off over the preset number of times, the control method returns to the step S702.
In view of the embodiments of the voltage regulator and the control method thereof, through monitoring the change of the output voltage, the control circuit may dynamically adjust the number of the switching transistors which are turned on to make the output voltage of the voltage regulator approach the reference voltage. Moreover, since the driving modules correspond to the switching transistors in the control circuit, the driving modules may operate through certain driving events so that the voltage regulator does not require a fixed clock signal to operate normally. Thus, there is only one driving module operating at a time point, and the static work current of the other driving modules is close to zero. This may not only reduce the waste of current in the control circuit but also prevent the occurrence of the inrush current.
Number | Date | Country | Kind |
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102147464 | Dec 2013 | TW | national |
This application claims the priority benefits of U.S. provisional application Ser. No. 61/891,722, filed on Oct. 16, 2013 and Taiwan application serial no. 102147464, filed on Dec. 20, 2013. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.
Number | Date | Country | |
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61891722 | Oct 2013 | US |