Shanghai Bright Power Semiconductor Co., Ltd.

Hanfei Yang

Zhen Zhu

Xiaoru Gao

Shungen Sun

Yihui Chen

Haifeng Miao

Yanmei Guo

Yuehui Li

A control circuit for a switched-mode power converter to generate a control signal for controlling switching transistors in the power converter is disclosed. The control circuit includes: a comparator; a ramp compensation circuit for producing and applying a ramp compensation signal to a first or second input of the comparator; an on-time generation circuit to generate an on-time timer signal; and a control signal generation circuit to generate, based on the comparison signal and the on-time timer signal, the control signal for controlling the switching transistors in the power converter. The ramp compensation signal output from the ramp compensation circuit is configured with: a first slope during an inductor demagnetization interval in operation of the power converter in CCM and a second slope during an inductor demagnetization interval and a zero-current interval in operation of the power converter in DCM, the first slope is greater than the second slope.

Power converter and control circuit thereof

A control circuit for an isolated power supply is disclosed, the control circuit includes a secondary-side drive signal generator, a secondary-side transistor switch turn-off detector and a primary-side control signal generator. The primary-side control signal generator is configured to: determine a second turn-on instant referring to an turn-off instant of the secondary-side synchronous rectification transistor from the turn-off acknowledgement signal; determine a first turn-on instant referring to a supposed turn-on instant for the primary-side transistor switch from the feedback signal of the output voltage of the isolated power supply; and determine the turn-on instant for the primary-side transistor switch from the second turn-on instant or the first turn-on instant whichever is later, and responsively generate the primary-side transistor switch control signal. This control circuit can effectively avoid shoot-through of primary- and secondary-side transistor switches at the cost of only insignificantly compromised feedback adjustment accuracy.

Control circuit for an isolated power supply

Isolated power supply control circuits, isolated power supply and control method thereof are disclosed, the control circuit for controlling an isolated power supply includes a secondary-side control signal generator and a primary-side control signal generator. The secondary-side control signal generator produces a secondary-side transistor switch control signal containing information about a turn-off instant of a secondary-side synchronous rectification transistor, which serves as a second turn-on instant. The primary-side control signal generator derives, from a feedback signal, a supposed turn-on instant for a primary-side transistor switch, which serves as a first turn-on instant. The primary side turn-on signal generator further derives a turn-on instant for the primary-side transistor switch from the second or first turn-on instant whichever is later and responsively generates a primary-side transistor switch control signal. This control circuit can effectively avoid shoot-through of primary- and secondary-side transistor switches at the cost of only insignificantly compromised feedback adjustment accuracy.

Isolated power supply control circuits, isolated power supply and control method thereof

A control circuit for a power converter comprising switching transistors and an output inductor is disclosed. One terminal of the output inductor serves as an output node, and another terminal of the output inductor serves as a switching node. The control circuit is configured to generate a control signal for controlling switching transistors in the power converter. The control circuit includes: a RC oscillator network connected to two terminals of the output inductor, the RC oscillator network configured to generate an oscillation signal containing a feedback ramp slope compensation component in response to a change in a voltage across the terminals of the output inductor; a comparator; an on-time generation circuit; and a control signal generation circuit to generate the control signal for controlling the switching transistors in the power converter.

Growing community of inventors

Shanghai, China

Hanfei Yang