Power supply circuit and dynamic voltage adjustment method

A power supply circuit, comprising:

• a clock buffer, configured to generate an adjusted clock signal according to a clock signal and a level control signal, wherein the clock signal comprises a preset level;
• a charge pump, coupled to the clock buffer, and configured to generate an output signal according to the adjusted clock signal and a system voltage;
• a control circuit, coupled to the charge pump, wherein the control circuit is configured to generate a charge pump control signal according to the output signal;
• and
• a first voltage clamp circuit, coupled between the control circuit and the clock buffer, and configured to receive the system voltage and the charge pump control signal, wherein the first voltage clamp circuit is configured to output the level control signal according to the charge pump control signal, wherein the adjusted clock signal comprises an adjusted level in response to a level of the level control signal,
• wherein the control circuit comprises:
• a constant current source, coupled to a first node, and configured to generate a first reference current flowing from the first node to a ground terminal, wherein the control circuit is configured to generate a second reference current according to the output signal and further generate the charge pump control signal according to the first reference current and the second reference current, and
• wherein the control circuit further comprises:
• a Zener diode, coupled to the charge pump, and configured to output a second reference current according to the output signal;
• and
• a first transistor, wherein a first terminal of the first transistor is coupled to the Zener diode, and a second terminal of the first transistor is coupled to the constant current source.

A dynamic voltage adjustment method, adapted to a power supply circuit, wherein the power supply circuit comprises a clock buffer, a charge pump, a control circuit and a voltage clamp circuit, wherein the charge pump is coupled to the clock buffer, the control circuit is coupled to the charge pump, the voltage clamp circuit is coupled between the control circuit and the clock buffer, wherein the dynamic voltage adjustment method comprises:

• generating, by the clock buffer, an adjusted clock signal according to a clock signal and a level control signal, wherein the clock signal comprises a preset level;
• generating, by the charge pump, an output signal according to the adjusted clock signal and a system voltage;
• generating, by the control circuit, a charge pump control signal according to the output signal;
• and
• receiving, by the voltage clamp circuit, the system voltage and generating the level control signal according to the charge pump control signal, wherein the adjusted clock signal comprises an adjusted level in response to a level of the level control signal,
• wherein generating the charge pump control signal according to the output signal by the control circuit comprises:
• charging or discharging a capacitor coupled between the control circuit and the voltage clamp circuit according to a first reference current and a second reference current to generate the charge pump control signal.