Synchronous Rectification Controller and Control Method Thereof
AssigneeLeadtrend Technology Corp.
InventorsTsung-Chien WU, Jun-Hao HUANG, Chung-Wei LIN, Ming-Chang TSOU
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Abstract
Disclosed is the source active region.
Claims20
A control method for synchronous rectification in use of a power supply having primary and secondary sides isolated from each other, wherein the power supply includes on the secondary side a synchronous rectifier with a control terminal, at which a control signal turns ON the synchronous rectifier to provide a channel approximately short-circuited if the control signal is greater than a threshold voltage, and turns OFF the synchronous rectifier to turn the channel into an open circuit if the control signal is between the threshold voltage and a ground reference voltage, the control method comprising:
- receiving a detection signal generated based on one end of the channel;
- comparing the detection signal with a predetermined level, wherein the predetermined level is higher than the ground reference voltage, and an excitation time is a period when the detection signal exceeds the predetermined level;
- checking if the excitation time lasts a preset time to generate a satisfaction signal;
- and
- precharging the control signal to a sub-threshold voltage between the threshold voltage and the ground reference voltage in response to the satisfaction signal.
A synchronous rectifier controller in use of a power supply with primary and second sides isolated from each other, wherein on the secondary side the power supply comprises a synchronous rectifier with a control terminal, a control signal at the control terminal turns ON the synchronous rectifier to provide a channel approximately short-circuited if the control signal exceeds a threshold voltage, the control signal substantially turns OFF the synchronous rectifier to turn the channel into an open circuit if the control signal is between the threshold voltage and a ground reference voltage, the synchronous rectifier controller comprising:
- a primary-side ON detector, comparing a detection signal at one end of the channel with a predetermined level, wherein the predetermined level is higher than the ground reference voltage, an excitation time is a period when the detection signal exceeds the predetermined level, and the primary-side ON detector provides a satisfaction signal if the excitation time lasts a preset time;
- and
- a precharge circuit precharging the control signal to a sub-threshold voltage between the threshold voltage and the ground reference voltage in response to the satisfaction signal.
A control method for controlling a synchronous rectifier with a control terminal, at which a control signal turns ON the synchronous rectifier to provide a channel approximately short-circuited if the control signal is greater than a threshold voltage, and turns OFF the synchronous rectifier to turn the channel into an open circuit if the control signal is between the threshold voltage and a ground reference voltage, wherein one end of the channel provides a detection signal, and the other end of the channel provides the ground reference voltage, the control method comprising:
- comparing the detection signal with a predetermined level to determine an excitation time, wherein the predetermined level is higher than the ground reference voltage, and the excitation time is a period when the detection signal exceeds the predetermined level;
- checking if the excitation time lasts a preset time to generate a satisfaction signal;
- and
- precharging the control signal to a sub-threshold voltage between the threshold voltage and the ground reference voltage in response to the satisfaction signal.
Dependencies are inferred from the claim text.