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US 8,913,363 B2Granted
Overcurrent protection circuit and overcurrent protection method
AssigneePanasonic Corporation
InventorsGo Takata, Yasunori Yamamoto
Life of this patent
Estimating the term…
Abstract
An overcurrent protection circuit includes: a determiner configured to determine whether or not the switch current exceeds a predetermined threshold, that is, the switch current is an overcurrent state when the switching element is turned ON; an OFF period setting counter configured to increase or decrease a counter output depending on a determination result of the determiner; and a drive signal generator configured to generate a drive signal of the switching element such that a length of an ON timing interval of the switching element corresponds to the counter output of the OFF period setting counter.
Claims20
An overcurrent protection circuit comprising:
- a switching element configured to adjust electric power by switching control, the electric power being supplied to a load;
- a current detector configured to detect a switch current flowing through the switching element;
- and
- a controller configured to perform the switching control of the switching element based on the switch current detected by the current detector, wherein:
- the controller includes:
- a determiner configured to determine whether or not the switch current exceeds a predetermined threshold, that is, the switch current is an overcurrent state when the switching element is turned ON;
- an OFF period setting counter configured to increase or decrease a counter output depending on a determination result of the determiner;
- and a drive signal generator configured to generate a drive signal of the switching element such that a length of an ON timing interval of the switching element corresponds to the counter output of the OFF period setting counter,
- the OFF period setting counter is configured to count up the counter output when the determiner determines that the switch current is the overcurrent state and count down the counter output when the determiner determines that the switch current is not the overcurrent state, and
- counting down the counter output per determination that the switch current is not the overcurrent state includes two or more steps of counting down from a current value to a base value.
7 more elements
An overcurrent protection method applied to a switching control device configured to supply electric power to a load, comprising the steps of:
- (i) when a switching element configured to adjust, by switching control, the electric power supplied to the load is turned ON, determining whether or not a switch current flowing through the switching element exceeds a predetermined threshold, that is, the current is an overcurrent state;
- (ii) increasing or decreasing a counter output depending on a determination result of the step (i);
- and
- (iii) depending on an increase or decrease of the counter output, determining a period in which the switching element is OFF, wherein:
- when it is determined that the switch current is the overcurrent state, the counter output is increased and when it is determined that the switch current is not the overcurrent state, the counter output is decreased, and
- counting down the counter output per determination that the switch current is not the overcurrent state includes two or more steps of counting down from a current value to a base value.
3 more elements
An overcurrent protection circuit comprising:
- an output terminal and a feedback terminal externally connectable each other;
- a drive signal generator configured to generate a drive signal, the drive signal generator including a PWM signal generator for generating a PWM signal internally within the drive signal generator, the PWM signal generator having an input connected to the feedback terminal and a reference voltage generator;
- a switching transistor having a node connected to the output terminal and a gate connected to the drive signal generator to receive the drive signal;
- a mask signal generator configured to generate a mask signal if an overcurrent condition occurred;
- and
- a counter for counting successive overcurrent condition, wherein:
- the drive signal generator further includes a logic gate, the logic gate having an input connected the PWM signal generator and the mask signal generator, and
- the mask signal is generated in consideration of a counting result of the counter.
5 more elements
An overcurrent protection circuit comprising:
- A first terminal and a second terminal;
- a drive signal generator configured to generate a drive signal, the drive signal generator including a PWM signal generator for generating a PWM signal internally within the overcurrent protection circuit, the PWM signal generator having a first input connected to the second terminal and a second input for receiving a reference voltage;
- a switching transistor having a node connected to the first terminal and a gate connected to the drive signal generator to receive the drive signal;
- a mask signal generator configured to generate a mask signal for masking the PWM signal;
- and
- a counter configured to be counted up if an overcurrent condition occurs, wherein:
- the drive signal generator further includes a logic gate, the logic gate having an input connected the PWM signal generator and the mask signal generator, and
- the mask signal is generated in consideration of a counting result of the counter.
5 more elements
Dependencies are inferred from the claim text.