Renesas Electronics America Inc.

Zheyuan Tan

A switched-mode power supply, such as a constant on time regulator, is presented. The switched-mode power supply includes a high side power switch coupled to a low side power switch at a switching node. A ramp injection circuit is coupled to the switching node and a ramp switch is coupled to the ramp injection circuit are also provided. A driver is used to drive the high side power switch and the low side power switch and to control the ramp switch. The driver turns off the ramp switch when the switch-mode power supply enters a tri-state, and turns the ramp switch back on when the switch-mode power supply exists the tri-state. The tri-state occurs when the switched-mode power supply operates in a discontinuous current mode, when both the high side power switch and the low side power switch are turned off.

Switching regulator with ramp injection switch

A switching converter with adjustable on-time is presented. The switching converter includes an inductor coupled to a power switch; a pulse generator generating a pulsed signal to switch the power switch and a controller. The pulsed signal has an on-time adjustable between a first value and a second value, the first value being shorter than the second value. The controller identifies a mode of operation between a continuous conduction mode and a discontinuous conduction mode and sets the on-time to the second value when a continuous conduction mode is identified. The controller also measures a duration between successive inductor current pulses, compares the duration with a first threshold value and maintains the on-time to the second value as long as the duration is less than the first threshold value. When the duration increases above the first threshold value the controller sets the on-time to the first value.

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San Jose, CA, United States of America

Zheyuan Tan