A device for switching power supply control

Abstract

The invention discloses a switching power supply control device and relates to the technical field of switching power supplies. The device includes a reference generation circuit, a sampling filter circuit, a comparator and a drive circuit; the reference generation circuit is used to output the first reference voltage and the second reference voltage; the sampling filter circuit is used to sample the output voltage and send the sampled voltage to A comparator; the first input end of the comparator is connected to the reference generation circuit to receive the first reference voltage or the second reference voltage, and the second input end is connected to the sampling filter circuit to receive the sampling voltage; the comparison The device is used to compare the first reference voltage or the second reference voltage with the sampling voltage, so as to output the comparison result to the driving circuit and the comparator, and the comparator selects to turn on the first reference voltage and the comparator according to the comparison result. one of the second reference voltages. The technical scheme of the invention greatly reduces the design difficulty of the subsequent filter circuit and also reduces the circuit cost.

Description

A device for switching power supply control technical field [0001] The present invention relates to the technical field of switching power supplies, in particular to a device for controlling switching power supplies. Background technique The current constant voltage switching power supply needs to accurately sample the output voltage by the sampling circuit, and then the feedback voltage is sent into the To the error amplifier, compared with the reference voltage, a pulse width modulated wave is generated to achieve a constant output voltage. However, when the sampling circuit When implemented by a resistor divider network, two voltage divider resistors are required, which increases the circuit cost and complexity; on the other hand, by Due to the stability problem of the switching power supply circuit, when compensating the error amplifier, a larger compensation capacitor is required, so that It will increase the circuit area or add external compensation components...

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Problems solved by technology

However, when the sampling circuit is implemented through a resistor divider network, two divider resistors are required, which increases the cost and complexity of the circuit; on the other hand, due to the stability problem of the switching power supply circuit, when compensating the error amplifier, A large compensation capacitor is required, which will increase the circuit area or add compensation components externally, further increasing the circuit cost; on the other hand, for the voltage-type PWM (Pulse width modulation, pulse width modulation) control method, the switching power supply circuit also Inductor current slope compensation is required to prevent sub-harmonic oscillation in the system, and the circuit design is difficult and costly

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