| CPC H02M 3/07 (2013.01) [H02M 1/36 (2013.01); H02M 3/158 (2013.01)] | 20 Claims |
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1. A supply circuit for a switched mode power supply (SMPS), wherein the SMPS comprises a high-side switching transistor and a low-side switching transistor, wherein the high-side switching transistor and the low-side switching transistor are connected through a switching node; the high-side switching transistor is driven by a high-side driver; the high-side switching transistor and the low-side switching transistor are switched to convert an input voltage into an output voltage; and the supply circuit comprises:
a first capacitor, a second capacitor, and a charging-discharging control circuit, wherein the first capacitor comprises a first terminal connected to the switching node, and a second terminal for providing a first supply voltage; the second capacitor comprises a first terminal connected to a reference ground or a first potential terminal under control of the charging-discharging control circuit, and a second terminal for providing a second supply voltage; and the first supply voltage and the second supply voltage are configured as supply sources for the high-side driver; and
the charging-discharging control circuit charges and discharges the second capacitor according to a charging-discharging enable signal, and specifically charges the second capacitor in a first time period, and discharges the second capacitor in a second time period, wherein a stable supply for the high-side driver is maintained.
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