Switching regulator control method
AssigneeAnpec Electronics Corporation
InventorsYueh-Lung Kuo, Chih-Yuan Chen
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Abstract
A control method for preventing an output voltage of a buck switching regulator from falling when an input voltage of the buck switching regulator falls includes: converting the input voltage into a charging current; determining a duty cycle of the buck switching regulator according to the charging current and the output voltage; and adjusting a switching frequency of a pulse width modulation signal in the buck switching regulator when the input voltage falls to a specific voltage and an off time of the pulse width modulation signal reaches a minimum value, in order to change the duty cycle to prevent the output voltage from falling.
Claims20
A control method for preventing an output voltage of a buck switching regulator from falling when an input voltage of the buck switching regulator falls, the control method comprising:
- converting the input voltage into a charging current;
- determining a duty cycle of the buck switching regulator according to the charging current and the output voltage;
- and
- adjusting a switching frequency of a pulse width modulation signal in the buck switching regulator when the input voltage falls to a specific voltage and an off time of the pulse width modulation signal reaches a minimum value, in order to change the duty cycle to prevent the output voltage from falling.
A control circuit for a buck switching regulator comprising:
- a voltage-to-current converter, for converting an input voltage of the buck switching regulator into a charging current;
- a current output device, coupled to the voltage-to-current converter, for outputting the charging current;
- a capacitor, coupled to the current output device, for storing the charging current;
- a switch, coupled to the capacitor, for discharging the capacitor;
- a comparing device, coupled to the voltage-to-current converter, for determining a duty cycle of the buck switching regulator according to the charging current and an output voltage of the buck switching regulator;
- and
- a duty cycle adjusting device, for adjusting a switching frequency of a pulse width modulation signal in the buck switching regulator when the input voltage falls to a specific voltage and an off time of the pulse width modulation signal reaches a minimum value, in order to change the duty cycle to prevent the output voltage from falling.
Dependencies are inferred from the claim text.