Abstract: An inrush current protection circuit for charging a load to a target voltage, in which the inrush current protection circuit includes a first charging circuit and a second charging circuit. The first charging circuit charges a load to a first stage voltage, and there is a voltage difference existing between the target voltage and the first stage voltage. The second charging circuit charges the load form the first stage voltage to the target voltage, in which the first charge circuit charges slower than the second charging circuit.

Abstract: A current regulating circuit includes a transistor and an operational amplifier. The transistor receives a load current and generates a feedback voltage corresponding to the load current. The operational amplifier receives a reference voltage and the feedback voltage to control the transistor. The operational amplifier further includes an input stage and an output stage. The input stage includes amplifier inputs each for alternately receiving the reference voltage and the feedback voltage so that the input stage generates operating voltages corresponding to the reference voltage and the feedback voltage. The output stage receives the operating voltages alternately to control the transistor. A driver and a method of current regulation are also disclosed herein.

Abstract: An LED driving circuit includes a control logic circuit, a dimming circuit and a counter. The control logic circuit is electrically coupled to an enable pin for receiving an input signal, and asserts an internal enable signal for activating the LED driving circuit. The dimming circuit is electrically coupled to the enable pin and outputs a control signal for controlling current flowing into at least one load connected to the LED driving circuit. The counter identifies the input signal based on a clock signal and asserts a detection signal for informing the control logic circuit of de-asserting the internal enable signal to de-activate the LED driving circuit when identifying the input signal as the enable signal being de-asserted for a predetermined period of the clock signal. A method of controlling an LED driving circuit is also disclosed herein.

Abstract: An inrush current protection circuit for charging a load to a target voltage, in which the inrush current protection circuit includes a first charging circuit and a second charging circuit. The first charging circuit charges a load to a first stage voltage, and there is a voltage difference existing between the target voltage and the first stage voltage. The second charging circuit charges the load form the first stage voltage to the target voltage, in which the first charge circuit charges slower than the second charging circuit.

Abstract: An over-current protection circuit includes a voltage generating unit and a comparing unit. The voltage generating unit is configured for receiving a first voltage and generating a reference voltage. The reference voltage has an offset positively dependent on temperature and negatively dependent on the first voltage, and the offset of the reference voltage varies along with another offset varying within a sense voltage sensed by the over-current protection circuit. The comparing unit is configured for comparing the reference voltage with the sense voltage to output a control signal for de-asserting the sense voltage when the sense voltage is correlated to an over-current condition of the sense voltage exceeding the reference voltage. A driver is also disclosed herein.

Abstract: A LED circuit is provided. The LED circuit comprises: an inductor, a group of LEDs, a power MOS and a switching circuit. The switching circuit comprises: an error amplifier generating an error output, a PWM, a RC circuit and a control means. The PWM generates a switching signal according to the error output to control the power MOS to charge or discharge the group of LEDs; the RC circuit comprises at least one first capacitor each comprising a switch, at least one second capacitors; and a resistive means connected in series between the first and the second capacitors and the error output. The control means generates a control signal according to the dimming signal to turn on the switches to activate the first capacitors during the active period of the dimming signal and turn off the switches to deactivate the first capacitors during the inactive period of the dimming signal.

Abstract: An over-current protection circuit includes a voltage generating unit and a comparing unit. The voltage generating unit is configured for receiving a first voltage and generating a reference voltage. The reference voltage has an offset positively dependent on temperature and negatively dependent on the first voltage, and the offset of the reference voltage varies along with another offset varying within a sense voltage sensed by the over-current protection circuit. The comparing unit is configured for comparing the reference voltage with the sense voltage to output a control signal for de-asserting the sense voltage when the sense voltage is correlated to an over-current condition of the sense voltage exceeding the reference voltage. A driver is also disclosed herein.

Abstract: A current regulating circuit includes a transistor and an operational amplifier. The transistor receives a load current and generates a feedback voltage corresponding to the load current. The operational amplifier receives a reference voltage and the feedback voltage to control the transistor. The operational amplifier further includes an input stage and an output stage. The input stage includes amplifier inputs each for alternately receiving the reference voltage and the feedback voltage so that the input stage generates operating voltages corresponding to the reference voltage and the feedback voltage. The output stage receives the operating voltages alternately to control the transistor. A driver and a method of current regulation are also disclosed herein.

Abstract: An operational amplifier includes an output unit, a voltage drop element and a feedback unit. The output unit is provided for sourcing an output current to an output of the operational amplifier when operating with a power unit for providing a current being multiple times the value of the output current. The voltage drop is provided for generating a voltage drop in accordance with the output current. The feedback unit is controlled with the voltage drop generated by the voltage drop element and controls the output unit and the power unit to regulate the output current in accordance with the voltage drop.

Abstract: An LED driving circuit includes a control logic circuit, a dimming circuit and a counter. The control logic circuit is electrically coupled to an enable pin for receiving an input signal, and asserts an internal enable signal for activating the LED driving circuit. The dimming circuit is electrically coupled to the enable pin and outputs a control signal for controlling current flowing into at least one load connected to the LED driving circuit. The counter identifies the input signal based on a clock signal and asserts a detection signal for informing the control logic circuit of de-asserting the internal enable signal to de-activate lo the LED driving circuit when identifying the input signal as the enable signal being de-asserted for a predetermined period of the clock signal. A method of controlling an LED driving circuit is also disclosed herein.

Abstract: A LED circuit is provided. The LED circuit comprises: an inductor, a group of LEDs, a power MOS and a switching circuit. The switching circuit comprises: an error amplifier generating an error output, a PWM, a RC circuit and a control means. The PWM generates a switching signal according to the error output to control the power MOS to charge or discharge the group of LEDs; the RC circuit comprises at least one first capacitor each comprising a switch, at least one second capacitors; and a resistive means connected in series between the first and the second capacitors and the error output. The control means generates a control signal according to the dimming signal to turn on the switches to activate the first capacitors during the active period of the dimming signal and turn off the switches to deactivate the first capacitors during the inactive period of the dimming signal.

Abstract: An operational amplifier includes an output unit, a voltage drop element and a feedback unit. The output unit is provided for sourcing an output current to an output of the operational amplifier when operating with a power unit for providing a current being multiple times the value of the output current. The voltage drop is provided for generating a voltage drop in accordance with the output current. The feedback unit is controlled with the voltage drop generated by the voltage drop element and controls the output unit and the power unit to regulate the output current in accordance with the voltage drop.

Abstract: A low drop out linear regulator is provided. The low drop out linear regulator comprises an output PMOS, a load, a discharging circuit and an operational amplifier. The output PMOS comprises a source connected to a power supply and a drain having an output voltage and an output current. The drain is connected to a load circuit having a heavy and a light load period. The load is connected to the drain to generate a divided output voltage. The discharging circuit is connected to the drain to discharge the output current from the drain. The operational amplifier is to generate a control voltage according to the divided output voltage and a reference voltage; when the load circuit switches from the heavy to the light load period to make the divided output voltage higher than the reference voltage, the control voltage turns off the output PMOS and activates the discharging circuit.

Abstract: A voltage regulated charge pump includes a charge pump circuit for receiving an input voltage to generate an output voltage, in which the charge pump circuit further includes a capacitor, a first switch and a second switch. The first switch is coupled between the input voltage and a first end of the capacitor. The second switch is coupled to the first end of the capacitor. The first and second switch are non-simultaneously turned on, so that the capacitor is charged to generate the output voltage. The voltage regulated charge pump further includes a third switch and a voltage regulating circuit. The third switch is coupled to the charge pump circuit. The voltage regulating circuit has an input receiving the output voltage and an output coupled to the third switch. The voltage regulating circuit modulates the third switch for regulating the output voltage generated by the charge pump circuit.

Abstract: A current biasing circuit is provided, which is designed to suppress reference current drift caused by temperature variation with a low overall temperature coefficient of a constant-voltage circuit and at least one resistor. The constant-voltage circuit comprises a diode and/or a diode-connected transistor. This current biasing circuit is based on a current mirror architecture, is easy to implement, and is a relatively temperature-independent current source.

Abstract: A current biasing circuit is provided, which is designed to suppress reference current drift caused by temperature variation with a low overall temperature coefficient of a constant-voltage circuit and at least one resistor. The constant-voltage circuit comprises a diode and/or a diode-connected transistor. This current biasing circuit is based on a current mirror architecture, is easy to implement, and is a relatively temperature-independent current source.

Abstract: A source and sink voltage regulator includes an output circuit, an amplifier circuit and a bias current control circuit. The output circuit is used to output a loading current under a stable output voltage and is further used to draw a reverse loading current while a loading voltage is greater than the output voltage. The amplifier circuit maintains the output voltage at a predetermined normal output voltage. The bias current control circuit keeps the transistors of the output circuit under a predetermined static bias current to accelerate the response speed of the voltage regulator, automatically maintaining a balance status while the output circuit is working.

Abstract: A source and sink voltage regulator includes an output circuit, an amplifier circuit and a bias current control circuit. The output circuit is used to output a loading current under a stable output voltage and is further used to draw a reverse loading current while a loading voltage is greater than the output voltage. The amplifier circuit maintains the output voltage at a predetermined normal output voltage. The bias current control circuit keeps the transistors of the output circuit under a predetermined static bias current to accelerate the response speed of the voltage regulator, automatically maintaining a balance status while the output circuit is working.