Balanced auxiliary on time generator for multiphase stackable constant on time control architecture

摘要

A control circuit configured to control a switching power supply including a ramp generator configured to generate a triangular waveform. A comparator is configured to generate a series of pulse width modulated (PWM) pulses at a first frequency and to regulate the switching power supply. The ramp generator includes a capacitor, a charging current source configured to provide a charging current to charge the capacitor, and a discharging current source configured to provide a discharging current to discharge the capacitor. The ramp generator also includes a closed loop current balancing current source configured to balance the currents from the charging and discharging current sources to establish a substantially zero direct current (DC) bias across the capacitor. The controller also includes a multi-phase configuration to provide a stackable multi-channel architecture.

主权项

1. A control circuit configured to control a switching power supply having an output, the control circuit comprising:
a ramp generator configured to generate a triangular waveform; a comparator having a first input configured to receive the triangular waveform and a second input configured to receive a first reference voltage, the comparator configured to generate a series of pulse width modulated (PWM) pulses at a first frequency and to regulate the switching power supply; wherein the ramp generator comprises a capacitor, and a current source configured to provide a charging current or discharging current to the capacitor; and wherein the ramp generator further comprises a closed loop current balancing source configured to provide the charging current or the discharging current to the capacitor to establish a substantially zero direct current (DC) bias across the capacitor.