Power conversion circuit of multi-phase power supply and multi-phase power supply and control method therefor
A power conversion circuit of a multi-phase power supply, a multi-phase power supply and a control method is provided. The power conversion circuit includes a PWM signal generating circuit, a driving circuit and a power circuit. The PWM signal generating circuit receives a counting code, generates a pulse width modulation signal when a count value characterized by the counting code is equal to their identification numbers, and controls on and off states of the switching transistor in the power circuit. Therefore, a plurality of phases of power conversion circuits in the multi-phase power supply may share one timing circuit to control on times of respective ones of the power conversion circuits, which is beneficial for reducing complexity and cost of the controller, and reducing circuit size and cost of the multi-phase power supply, and for implementation of a multi-phase power supply with higher phase numbers.
1 . A power conversion circuit of a multi-phase power supply, wherein the multi-phase power supply comprises N-phases of power conversion circuits, where N is a positive integer greater than 1, wherein the power conversion circuit comprises:
a PWM signal generating circuit which receives a counting code and generates a pulse width modulation signal when the counting code meets a predetermined condition;
a driving circuit which converts the pulse width modulation signal into a switch driving signal; and
a power circuit which includes at least one switching transistor with on and off states being controlled by the switch driving signal to provide an output voltage of respective one of the N-phases in accordance with an input voltage,
wherein the predetermined condition is met when a count value represented by the counting code is equal to an identification number of the power conversion circuit,
wherein the counting code comprises a first counting code and a second counting code,
the PWM signal generating circuit is configured to generate an on signal when the first counting code meets the predetermined condition, which the on signal is used for determining an on time of the at least one switching transistor, and to generate an off signal when the second counting code meets the predetermined condition, which the off signal is used for determining an off time of the at least one switching transistor, and the pulse width modulation signal is obtained according to the on signal and the off signal.
2 . The power conversion circuit according to claim 1 , wherein the first counting code is generated in response to a first timing signal that characterizes a sequence change of the N-phases of power conversion circuits of the multi-phase power supply,
the second counting code is generated in response to a second timing signal which is delayed by a predetermined time with respect to the first timing signal.
3 . The power conversion circuit according to claim 2 , wherein the first counting code and the second counting code are changed at each clock edge of the first timing signal and the second timing signal, respectively, to repeatedly output N count values in sequence.
4 . The power conversion circuit according to claim 3 , wherein the N count values correspond to the identification numbers of the N-phases of power conversion circuits, respectively.
5 . The power conversion circuit according to claim 2 , wherein the second timing signal is generated in response to a phase difference between the on signal and the off signal of the power conversion circuit, a predetermined time offset, an error between the output voltage and the expected voltage of the multi-phase power supply, and/or variation in an input voltage of the multi-phase power supply.
6 . A multi-phase power supply comprising:
N-phases of power conversion circuits according to claim 1 , wherein N is a positive integer greater than 1; and
a multi-phase power supply controller which is configured to provide the counting code to the N-phases of power conversion circuits for controlling each of the N-phases of power conversion circuits to generate the output voltage according to the input voltage,
wherein each of the N-phases of power conversion circuits includes the power conversion circuit which has the identification number equal to the count value represented by the counting code.
7 . The multi-phase power supply according to claim 6 , wherein the counting code comprises a first counting code and a second counting code, and each of the N-phases of power conversion circuits is configured to generate an on signal in accordance with the first counting code and an off signal in accordance with the second counting code,
wherein the on signal is used for determining an on time of at least one switching transistor in each of the N-phases of power conversion circuits, and the off signal is used for determining an off time of at least one switching transistor in each of the N-phases of power conversion circuits.
8 . The multi-phase power supply according to claim 7 , wherein the multi-phase power supply controller comprises:
an on-timing control circuit for generating a first timing signal, wherein the first timing signal is used for characterizing a sequence change of the N-phases of power conversion circuits;
a first counter configured to perform counting in response to the first timing signal to generate the first counting code;
an off-timing control circuit for generating a second timing signal, wherein the second timing signal is delayed by a predetermined time with respect to the first timing signal; and
a second counter configured to perform counting in response to the second timing signal to generate the second counting code.
9 . The multi-phase power supply according to claim 8 , wherein the first counting code and the second counting code change at each clock edge of the first timing signal and the second timing signal, respectively, to repeatedly output N count values in sequence.
10 . The multi-phase power supply according to claim 9 , wherein the N count values correspond to identification numbers of the N-phases of power conversion circuits, respectively.
11 . The multi-phase power supply according to claim 8 , wherein the on-timing control circuit is implemented with a phase-locked oscillator.
12 . The multi-phase power supply according to claim 8 , wherein the off-timing control circuit is implemented with a phase-locked loop circuit, and comprises:
a frequency and phase detector for receiving the on signal and the off signal of each of the N-phases of power conversion circuits and obtaining a phase difference between the on signal and the off signal;
a delay control unit configured to generate a voltage control signal in response to the phase difference between the on signal and the off signal, a predetermined time offset, an error between an output voltage and an expected voltage of the multi-phase power supply, and/or variation in the input voltage of the multi-phase power supply; and
a voltage-controlled oscillator configured to generate the second timing signal in accordance with the voltage control signal.
13 . The multi-phase power supply according to claim 8 , wherein the multi-phase power supply controller further comprises:
a cross-cycle control circuit for receiving the first and second counting codes, providing a correction signal to the N-phases of power conversion circuits according to a delay between the first and second counting codes, the correction signal being used for avoiding that the delay overshoots to a previous voltage cycle or lags behind to a later voltage cycle.
14 . A control method for the multi-phase power supply comprising N-phases of power conversion circuits according to claim 1 , where N is a positive integer greater than 1, wherein the control method comprises:
generating a first timing signal for characterizing a sequence change of the N-phases of power conversion circuits;
generating a first counting code by performing counting in response to the first timing signal;
generating a second timing signal, the second timing signal being delayed by a predetermined time with respect to the first timing signal;
generating a second counting code by performing counting in response to the first timing signal; and
generating the output voltage in accordance with the input voltage in response to the first counting code and the second counting code in each of the N-phases of power conversion circuits, wherein each of the N-phases of power conversion circuits includes the power conversion circuit which has the identification number equal to the count value represented by the first counting code and the second counting code.
15 . The control method according to claim 14 , wherein the step of generating the output voltage in accordance with the input voltage in response to the first counting code and the second counting code in each of the N-phases of power conversion circuits comprises:
generating an on signal in accordance with the first counting code and generating an off signal in accordance with the second counting code in each of the N-phases of power conversion circuits, wherein the on signal is used for determining an on time of at least one switching transistor in each of the N-phases of power conversion circuits, and the off signal is used for determining an off time of the at least one switching transistor in each of the N-phases of power conversion circuits.
16 . The control method according to claim 14 , wherein the first counting code and the second counting code change at each clock edge of the first timing signal and the second timing signal, respectively, to repeatedly output N count values in sequence.
17 . The control method according to claim 16 , wherein the N count values correspond to identification numbers of the N-phases of power conversion circuits, respectively.
18 . The control method according to claim 14 , wherein the step of generating the second timing signal comprises:
generating the second timing signal in response to a phase difference between an on signal and an off signal of each of the N-phases of power conversion circuits, a predetermined time offset, an error between the output voltage and an expected voltage of the multi-phase power supply, and/or variation in the input voltage of the multi-phase power supply.
19 . The control method according to claim 14 , further comprising: providing a correction signal to the N-phases of power conversion circuits according to a delay between the first counting code and the second counting code, the correction signal being used for avoiding that the delay overshoots to a previous voltage cycle or lags behind to a later voltage cycle.