SOFT-OFF CONTROL CIRCUIT, POWER CONVERTER AND ASSOCIATED CONTROL METHOD
First Claim
1. A soft-off control circuit for controlling a soft-off procedure of a power converter, wherein the power converter comprises a main switch and is configured to receive an input voltage and to provide an output voltage based on driving the main switch to switch on and off, and wherein the power converter further comprises a soft-start/soft-off pin configured to provide a variable reference signal;
- the soft-off control circuit comprising;
a first input terminal configured to receive the input voltage of the power converter;
a second input terminal configured to receive an enable signal, wherein the enable signal has a first enable state for controlling the power converter to shut off and start the soft-off procedure and a second enable state for controlling the power converter to power on;
a third input terminal configured to receive an over-voltage threshold, wherein the over-voltage threshold is designed to indicate an over-voltage of the input voltage during the soft-off procedure; and
an output terminal configured to provide a soft-off control signal;
whereinthe soft-off control circuit is configured to generate the soft-off control signal at least based on the enable signal, the input voltage and the over-voltage threshold, and wherein when the enable signal is at the first enable state, the soft-off control signal is configured to control the variable reference signal to increase when the input voltage is higher than the over-voltage threshold, and to control the variable reference signal to decrease when the input voltage is lower than the over-voltage threshold.
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Accused Products
Abstract
A power converter having a soft-off control circuit and a variable reference signal generation module and associated method for controlling the power converter. The variable reference signal generation module is configured to provide a variable reference signal to the power converter. The soft-off control circuit is configured to determine whether an input voltage of the power converter exceeds an over-voltage threshold, and to control the variable reference signal to increase once the input voltage reaches the over-voltage threshold and to decrease when the input voltage is lower than the over-voltage threshold. The power converter can regulate an output voltage to increase with the increase of the variable reference signal and to decrease with the decrease of the variable reference signal so that during a soft-off procedure the input voltage may not exceed the over-voltage threshold, enabling the power converter to be safely shut off.
25 Citations
18 Claims
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1. A soft-off control circuit for controlling a soft-off procedure of a power converter, wherein the power converter comprises a main switch and is configured to receive an input voltage and to provide an output voltage based on driving the main switch to switch on and off, and wherein the power converter further comprises a soft-start/soft-off pin configured to provide a variable reference signal;
- the soft-off control circuit comprising;
a first input terminal configured to receive the input voltage of the power converter; a second input terminal configured to receive an enable signal, wherein the enable signal has a first enable state for controlling the power converter to shut off and start the soft-off procedure and a second enable state for controlling the power converter to power on; a third input terminal configured to receive an over-voltage threshold, wherein the over-voltage threshold is designed to indicate an over-voltage of the input voltage during the soft-off procedure; and an output terminal configured to provide a soft-off control signal;
whereinthe soft-off control circuit is configured to generate the soft-off control signal at least based on the enable signal, the input voltage and the over-voltage threshold, and wherein when the enable signal is at the first enable state, the soft-off control signal is configured to control the variable reference signal to increase when the input voltage is higher than the over-voltage threshold, and to control the variable reference signal to decrease when the input voltage is lower than the over-voltage threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- the soft-off control circuit comprising;
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13. A power converter having a normal operation and a soft-off procedure, the power converter comprising:
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an input port configured to receive an input voltage; an output port configured to provide an output voltage; a switch module at least comprising a main switch configured to switch on and off based on a driving signal to convert the input voltage to the output voltage; a control module having a first control input terminal, a second control input terminal, a third control input terminal and a control output terminal, wherein the first control input terminal is configured to receive a feedback signal indicative of the output voltage, and wherein the second control input terminal is configured to receive a constant reference signal indicative of a desired value of the output voltage, and wherein the third control input terminal is configured to receive a variable reference signal, and wherein the control module is configured to provide the driving signal at least based on processing the feedback signal and the constant reference signal during the normal operation, and wherein the control module is further configured to provide the driving signal at least based on processing the feedback signal and the variable reference signal during the soft-off procedure; and a variable reference signal generation module configured to provide a variable reference signal to the power converter;
whereinthe variable reference signal generation module comprises a soft-off control circuit configured to control the soft-off procedure of the power converter through controlling the variable reference signal; and
whereinthe soft-off control circuit has a first input terminal configured to receive the input voltage of the power converter, a second input terminal configured to receive an enable signal, a third input terminal configured to receive an over-voltage threshold and an output terminal configured to provide a soft-off control signal;
wherein the enable signal has a first enable state for controlling the power converter to shut off and start the soft-off procedure and a second enable state for controlling the power converter to power on; and
wherein the over-voltage threshold is designed to indicate an over-voltage of the input voltage during the soft-off procedure; and
whereinthe soft-off control circuit is configured to generate the soft-off control signal at least based on the enable signal, the input voltage and the over-voltage threshold, and wherein when the enable signal is at the first enable state, the soft-off control signal is configured to control the variable reference signal to increase when the input voltage is higher than the over-voltage threshold, and to control the variable reference signal to decrease when the input voltage is lower than the over-voltage threshold. - View Dependent Claims (14)
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15. A method for controlling a power converter, wherein the power converter comprises at least a main switch and is configured to convert an input voltage to an output voltage based on driving the main switch to switch on and off, and wherein the power converter has a soft-off procedure, the method for controlling the power converter comprising:
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sensing the output voltage to provide a feedback signal indicative of the output voltage; generating a variable reference signal; sensing the input voltage during the soft-off procedure and comparing the input voltage with an over-voltage threshold to provide a soft-off control signal; applying the soft-off control signal to control the variable reference signal to increase when the input voltage is higher than the over-voltage threshold; applying the soft-off control signal to control the variable reference signal to decrease when the input voltage is lower than the over-voltage threshold during the soft-off procedure; and regulating the output voltage based on the variable reference signal and the feedback signal during the soft-off procedure, so as to control the output voltage to decrease with the decrease of the variable reference signal and increase with the increase of the variable reference signal. - View Dependent Claims (16, 17, 18)
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Specification