Disclosed is a power supply that automatically switches between a voltage regulation mode and an over current protection mode, as needed. The power supply includes a voltage regulator that generates a first control voltage for applying to the control terminal of a pass transistor during a voltage regulation mode to maintain an output voltage at a desired voltage level. The power supply includes a current limiter that generates a second control voltage for applying to the control terminal of the pass transistor during an over current protection mode to prevent an output current from rising above a maximum output current limit. The power supply includes additional circuitry that detects when over current protection is required and automatically switches the control voltage applied to the control terminal from the first control voltage to the second control voltage or vice versa, as necessary. Also disclosed is an associated power supply method.

Disclosed is a power supply that automatically switches between a voltage regulation mode and an over current protection mode, as needed. The power supply includes a voltage regulator that generates a first control voltage for applying to the control terminal of a pass transistor during a voltage regulation mode to maintain an output voltage at a desired voltage level. The power supply includes a current limiter that generates a second control voltage for applying to the control terminal of the pass transistor during an over current protection mode to prevent an output current from rising above a maximum output current limit. The power supply includes additional circuitry that detects when over current protection is required and automatically switches the control voltage applied to the control terminal from the first control voltage to the second control voltage or vice versa, as necessary. Also disclosed is an associated power supply method.

A current detection circuit includes normally-on-type and a first normally-off-type switching elements with main current paths that are connected in series, and a second normally-off-type switching element that has a source and a gate that are connected to a source and a gate of the first normally-off-type switching element and a drain that is connected to a constant current source, and executes a division process by using drain voltages of the two normally-off-type switching elements.

A current detection circuit includes normally-on-type and a first normally-off-type switching elements with main current paths that are connected in series, and a second normally-off-type switching element that has a source and a gate that are connected to a source and a gate of the first normally-off-type switching element and a drain that is connected to a constant current source, and executes a division process by using drain voltages of the two normally-off-type switching elements.

A method and apparatuses for power regulation using an extended current limit are disclosed. The power regulator detects an occurrence of an output current of the regulator exceeding a first current limit, triggers an extended current limit timer based on the detected occurrence, regulates the output current according to a second current limit higher than the first current limit based on a duration of the extended current limit timer, and regulates the output current according to the first current limit based on an expiration of the duration of the extended current limit timer.

Disclosed is a power supply that automatically switches between a voltage regulation mode and an over current protection mode, as needed. The power supply includes a voltage regulator that generates a first control voltage for applying to the control terminal of a pass transistor during a voltage regulation mode to maintain an output voltage at a desired voltage level. The power supply includes a current limiter that generates a second control voltage for applying to the control terminal of the pass transistor during an over current protection mode to prevent an output current from rising above a maximum output current limit. The power supply includes additional circuitry that detects when over current protection is required and automatically switches the control voltage applied to the control terminal from the first control voltage to the second control voltage or vice versa, as necessary. Also disclosed is an associated power supply method.

Disclosed is a power supply that automatically switches between a voltage regulation mode and an over current protection mode, as needed. The power supply includes a voltage regulator that generates a first control voltage for applying to the control terminal of a pass transistor during a voltage regulation mode to maintain an output voltage at a desired voltage level. The power supply includes a current limiter that generates a second control voltage for applying to the control terminal of the pass transistor during an over current protection mode to prevent an output current from rising above a maximum output current limit. The power supply includes additional circuitry that detects when over current protection is required and automatically switches the control voltage applied to the control terminal from the first control voltage to the second control voltage or vice versa, as necessary. Also disclosed is an associated power supply method.

A power transistor generates an output current and a sense transistor generates a proportional sense current. A differential amplifier generates a gate voltage applied to the power and sense transistors in response to first and second input signals. A comparator circuit compares the gate voltage to a switching reference to detect whether the power and sense transistors are operating in a triode mode of operation or in a saturation mode of operation. At least one of the first and second input signals is modified in response to the detection made by the comparator circuit. In one instance, different reference voltages are applied to an input of the amplifier depending on the detected mode of operation. In another instance, different resistances are used to convert the sense current to a voltage for application to an input of the amplifier in response to the detected mode of operation.

A power transistor generates an output current and a sense transistor generates a proportional sense current. A differential amplifier generates a gate voltage applied to the power and sense transistors in response to first and second input signals. A comparator circuit compares the gate voltage to a switching reference to detect whether the power and sense transistors are operating in a triode mode of operation or in a saturation mode of operation. At least one of the first and second input signals is modified in response to the detection made by the comparator circuit. In one instance, different reference voltages are applied to an input of the amplifier depending on the detected mode of operation. In another instance, different resistances are used to convert the sense current to a voltage for application to an input of the amplifier in response to the detected mode of operation.

An overcurrent protection circuit limits a monitoring target current to or below a limit current value IOCP. For example, it can operate so as to give the limit current value IOCP, when temperature Tj is lower than a threshold value Tx, a flat temperature response and, when temperature Tj is higher than the threshold value Tx, a negative temperature response. For another example, it can operate so as to set the limit current value IOCP, when temperature Tj is lower than a threshold value Tx, at a first limit current value IOCP having a flat temperature response and, when temperature Tj is higher than the threshold value Tx, at a second limit current value IOCP having a flat temperature response and lower than the first limit current value IOCP.