Switching regulator control circuit, switching regulator and switching regulator control method
View Patent ↗Provides a switching regulator control circuit, a switching regulator and a switching regulator control method for achieving low current consumption and quick response at normal operating time. A change-over switch MFB for opening/closing the phase compensation is provided to establish both the quick responsibility using a gain of an error amplifier EA provided with no phase compensation and stability of control system provided with phase compensation. By turning the change-over switch MFB non-conductive at a timing in which the PMOS transistor M 1 turns to conductive, the phase compensation between the input and output of the error amplifier EA is cut off. A detection voltage VM is amplified in term of error with a gain of the error amplifier EA itself. A quick transient response to changes in the output voltage VOUT is achieved corresponding to maximum response characteristic. Phase compensation between the input and output of the error amplifier EA is formed by turning the change-over switch MFB conductive at a timing in which the PMOS transistor M 1 turns to non-conductive. Consequently, stability of the control system can be secured.
1. A switching regulator control circuit for a switching regulator for controlling an output voltage by repeating supply of electric power corresponding to ON/OFF of a switch device, comprising:
an error amplifier for amplifying a voltage difference between the output voltage and desired voltage, and
a phase compensation section which is connected in between the input and output of the error amplifier so as to stabilize the operating condition of a control system,
wherein the switching regulator further comprises a phase compensation quantity switching section for reducing the phase compensation quantity of the phase compensation section in a predetermined period containing a timing in which conduction of the switch device is started.
2. The switching regulator control circuit according to claim 1 , wherein the phase compensation quantity switching section reduces the phase compensation quantity by cutting off a compensation pass in the phase compensation section.
3. The switching regulator control circuit according to claim 1 , wherein the predetermined period is set up corresponding to a conduction control signal of the switch device.
4. The switching regulator control circuit according to claim 3 , wherein the switching regulator is a step-down converter and the phase compensation quantity switching section reduces the phase compensation quantity corresponding to the conduction control signal which turns the switch device conductive.
5. The switching regulator control circuit according to claim 3 , wherein the switching regulator is a boosting converter and the phase compensation quantity switching section reduces the phase compensation quantity corresponding to the conduction control signal which turns the switch device conductive.
6. The switching regulator control circuit according to claim 3 , wherein the predetermined period is set up synchronously with the conduction control signal.
7. The switching regulator control circuit according to claim 3 , wherein the predetermined period is started prior to a start of the conduction control signal.
8. The switching regulator control circuit according to claim 3 , wherein the predetermined period is ended prior to an end of the conduction control signal.
9. The switching regulator control circuit according to claim 3 , wherein ON/OFF of the switch device is performed in a predetermined cycle and the predetermined period is a period fixed since a timing in which conduction of the switch device is started in the predetermined cycle.
10. The switching regulator control circuit according to claim 1 , wherein the phase compensation section is provided with plural capacitor devices connected in parallel and the phase compensation quantity switching section is provided on part of the plural capacitor devices.
11. The switching regulator control circuit according to claim 1 wherein the phase compensation section is provided with a capacitor device and a resistor device connected in series and the phase compensation quantity switching section bypasses the resistor device.
12. A switching regulator for controlling an output voltage by repeating supply of electric power corresponding to ON/OFF of a switch device, the switching regulator comprising:
an error amplifier for amplifying a voltage difference between the output voltage and desired voltage; and
a phase compensation section which is connected in between the input and output of the error amplifier so as to stabilize the operating condition of a control system,
wherein the switching regulator further comprises a phase compensation quantity switching section for reducing the phase compensation quantity of the phase compensation section in a predetermined period containing a timing in which conduction of the switch device is started.
13. A switching regulator control method in which a voltage difference between an output voltage and desired voltage is amplified in terms of error and an output voltage is negatively fed back so as to stabilize the operating condition of the control system, the switching regulator control method comprising:
A step of controlling the output voltage by repeating supply of electric power corresponding to ON/OFF of a switch device; and
a step of reducing the phase compensation quantity of the phase compensation in a predetermined period containing a timing in which the conduction of the switch device is started.