Abstract: A buck circuit having a fast transient response mechanism is provided. The buck circuit comprises a high side MOS, a low side MOS, a transient control module and an operation control module. The low side MOS is connected to the high side MOS at a connection point for generating an output voltage to an external load according to an input voltage from the high side MOS. The operation control module controls the operation of the high and the low side MOS according to the output voltage when the external load is in a heavy load state such that the transient control module is disabled. When the external load turns from the heavy load state to a light load state such that the output voltage raises over a predetermined level, the transient control module is enabled to turn on the low side MOS for discharging to pull down the output voltage.

Abstract: A voltage selection circuit selecting a minimum voltage from the remainder voltages outputted from the light emitting diode channels is disclosed. The voltage selection circuit includes a first picking circuit, which has the first operation amplifiers, a positive input terminal, an output terminal, a negative input terminal, and an output stage. Each of the first operation amplifiers includes a positive input terminal, an output terminal, a negative input terminal, and an output stage. The positive input terminal receives one of the remainder voltages from one of the first ends of the light emitting diode channels. The output terminal outputs the minimum voltage, in which the output terminals of the first operation amplifiers are connected together. The negative input terminal is electrically connected to the output terminal. The output stage is electrically connected to the output terminal, in which the output stage has current sinking ability stronger than current sourcing ability.

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: A power-off control circuit adapted in a LCD panel comprising a gate pulse modulator and a level shifter is provided. The power-off control circuit comprises a logic gate and a control switch. The logic gate comprises a first input to receive an internal power supply, a second input to receive a power state signal and a logic output to generate a control signal. When the power supply is on, the internal power supply is on and the power state signal is in a first state to make the control signal turn off the control switch. When the power supply is off, the internal power supply is on and the power state signal is in a second state to make the control signal turn on the control switch to make the gate pulse modulator makes pixels of a pixel array to perform a discharge activity.

Abstract: An error amplifier and a LED circuit comprising the same are provided. The LED circuit comprises an inductor, a group of LEDs and a power MOS connected to the inductor, an error amplifier and a pulse width modulator controlling the gate of the power MOS according to an error amplifier output. The error amplifier comprises a differential input stage, an output stage having a first NMOS, a first PMOS, a second NMOS, a second PMOS and a control switch module. During a first operation mode, the control switch module connects the first NMOS and PMOS and connects the second NMOS and PMOS, and during a second operation mode, control switch module disables the second NMOS and PMOS.

Abstract: A LED circuit is provided. The LED circuit comprises: a plurality of LED channels, a driving module and a feedback-selecting module. The driving module supplies a driving voltage to the plurality of LED channels according to a feedback voltage. The feedback-selecting module comprises an open detection unit and a minimum-selecting unit. The open detection unit performs an open detection mechanism to separate the plurality of LED channels into a plurality of open LED channels and a plurality of non-open LED channels having an output voltage respectively. The minimum-selecting unit performs a selection mechanism to select a minimum output voltage as the feedback voltage from the output voltage of each of the plurality of non-open LED channels. A LED circuit operation method adapted in the LED circuit is provided herein as well.

Abstract: A detection circuit is disclosed in specification and drawing, where the detection circuit includes a current source, a voltage-current converter and a current comparator. The voltage-current converter is configured to acquire a receiving current from the current source by comparing a reference voltage with an input voltage of a detecting terminal. The current comparator is configured to output an output voltage by comparing a steady current with an output current based on the receiving current.

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 trimming circuit is provided. The trimming circuit had at least a trimming cell, and each of the at least trimming cell includes three current paths and a fuse. A first one of the current paths is interrupted when a second one of the current paths is uninterrupted, and the first one of the current paths is uninterrupted when the second one of the current paths is interrupted. When a trimming control signal is at an enable state, a third one of the current paths is uninterrupted, such that the fuse is blown. Based on the status of the fuse, the trimming circuit is capable of trimming an output voltage or an output current of an electric apparatus.

Abstract: A LED driving circuit having a smooth transient mechanism adapted in a LED circuit to drive a plurality of LED channels is provided. The LED driving circuit comprises: a dimming module, a dc-to-dc converter, a delay module and a plurality of current sink modules. A control module of the dc-to-dc converter generates a driving voltage according to the dimming voltage from the dimming module to control a gate of a power MOS to further turn on or turn off the LED channels. The delay module comprises delay units connected in series to delay the dimming voltage to generate a plurality of delay signals each at an output node of each of the delay units. Each of the current sink modules is connected to one of the LED channels to adjust the turn-on period according to one of the delay signals. A LED circuit operation method is disclosed herein as well.

Abstract: A LED circuit is provided. The LED circuit comprises LED channels and a LED driving circuit. The LED driving circuit comprises: a current mirror, a dc-to-dc converter and current sink modules each connected between one of the LED channels and an output load to lock the voltage at the output load at a level of a setting voltage. The current mirror comprises an input branch to generate an input setting current according to a variable setting load and an output branch to generate an output setting current to further generate a variable reference voltage and the setting voltage. A control module of the dc-to-dc converter generates a driving voltage according the variable reference voltage and a feedback voltage to control a gate of the power MOS of the dc-to-dc converter to further control the operation of the LED channels. A LED circuit operation method is disclosed herein as well.

Abstract: A buck circuit having a fast transient response mechanism is provided. The buck circuit comprises a high side MOS, a low side MOS, a transient control module and an operation control module. The low side MOS is connected to the high side MOS at a connection point for generating an output voltage to an external load according to an input voltage from the high side MOS. The operation control module controls the operation of the high and the low side MOS according to the output voltage when the external load is in a heavy load state such that the transient control module is disabled. When the external load turns from the heavy load state to a light load state such that the output voltage raises over a predetermined level, the transient control module is enabled to turn on the low side MOS for discharging to pull down the output voltage.

Abstract: A channel detection device is disclosed in specification and drawing, where the channel detection circuit includes a disable circuit, LED pins, receivers and an error detection circuit. The disable circuit sends a disabling pulse to one or some LED pins of the plurality of LED pins, where the one or some LED pins are connected to the disable circuit. Each of the receivers is connected to one of the plurality of LED pins respectively and is capable of outputting an inhibiting signal when the LED pin connected receives the disabling pulse from the disable circuit. The error detection circuit is coupled to the receivers and the LED pins. The error detection circuit is configured to detect open-circuit of some LED pins of the plurality of LED pins, and bypass the detection of open-circuit of some other LED pin of which the receiver outputs the inhibiting signal.

Abstract: A light emitting diode driving circuit includes a DC-to-DC voltage converter, a pulse width modulator, a shifting circuit, and a plurality of current sink circuits. The DC-to-DC voltage converter generates a driving voltage on first ends of the light emitting diode channels, in which the DC-to-DC voltage converter includes a switch, and a magnitude of the driving voltage is correlated with the conduction time of the switch. The pulse width modulator generates a PWM signal having a duty cycle which drives the switch of the DC-to-DC voltage converter. The plurality of clock cycles on the shifting circuit delays the PWM signal to generate a plurality of phase signals, in which the phase signals have different phases. The current sink circuits are positioned to control the flows of current flowing through the light emitting diode channels according to the phase signals having different phases.

Abstract: A light emitting diode driving circuit includes connected driving units, each of which is configured for driving multiple channels of light emitting diodes generating a feedback voltage for the corresponding driving unit. Each of the driving units includes a selection circuit for comparing the feedback voltage with an input voltage to output a smaller one of the feedback voltage and the input voltage to a next one of the driving units, as the input voltage for the next one of the driving units.

Abstract: A voltage selection circuit selecting a minimum voltage from the remainder voltages outputted from the light emitting diode channels is disclosed. The voltage selection circuit includes a first picking circuit, which has the first operation amplifiers, a positive input terminal, an output terminal, a negative input terminal, and an output stage. Each of the first operation amplifiers includes a positive input terminal, an output terminal, a negative input terminal, and an output stage. The positive input terminal receives one of the remainder voltages from one of the first ends of the light emitting diode channels. The output terminal outputs the minimum voltage, in which the output terminals of the first operation amplifiers are connected together. The negative input terminal is electrically connected to the output terminal. The output stage is electrically connected to the output terminal, in which the output stage has current sinking ability stronger than current sourcing ability.

Abstract: A charge pump driving circuit for generating a driving pulse signal to drive a charge pump circuit is disclosed. The charge pump driving circuit includes a control signal generator and a driving signal generator. The control signal generator generates a first control signal, a second control signal, and a third control signal, in which the third control signal transits in the first place, the first control signal transits next, and the second control signal transits last. The driving signal generator, controlled by the first control signal, the second control signal and the third control signal, generates the driving pulse signal, in which the driving signal generator has a rare short circuit current flowing from a supply terminal providing a supply voltage to a ground terminal providing a ground voltage.

Abstract: A switching circuit adapted in an LED circuit and an LED circuit are provided. The switching circuit has a mode-selecting circuit, a comparator and a control module. The mode-selecting circuit has a voltage-dividing module and a switch. The voltage-dividing module receives and divides a reference voltage to further generate a working voltage. The switch is connected to the voltage-dividing module, wherein the switch has an output. The comparator comprises a first input connected to the switch, a second input and a comparator output. During a measuring mode, the switch transfers the reference voltage and the second input is connected to the comparator output. During a working mode, the switch transfers the working voltage, the second input of the comparator receives an output voltage of the LED circuit and the control module generates a control signal according to the voltage of the comparator output to switch the LED circuit.

Abstract: A detection circuit is disclosed in specification and drawing, where the detection circuit includes a current source, a voltage-current converter and a current comparator. The voltage-current converter is configured to acquire a receiving current from the current source by comparing a reference voltage with an input voltage of a detecting terminal. The current comparator is configured to output an output voltage by comparing a steady current with an output current based on the receiving current.