Abstract: An LED driver includes a power converter to convert an input voltage to a regulated voltage, a current source to be connected with an LED string in series between the power converter and a bias node, and a switching circuit to apply a bias voltage to the bias node to set the total voltage drop of the LED string and the current source. By controlling the total voltage drop of the LED string and the current source, the LED driver will automatically select a boost mode or a buck mode for operation, thereby improving the efficiency thereof.

Abstract: A temperature detecting circuit and method thereof, adapted to a voltage converter circuit which includes a current detecting circuit having a detecting output port outputting a current detecting signal proportional to an output current of the voltage converter circuit, includes: a current signal processing unit, having a signal input port coupling to the detecting output port, a first detecting output port generating a first processing signal with a first temperature coefficient, a second detecting output port generating a second processing signal with a second temperature coefficient, wherein the first and the second processing signals are proportional to the current detecting signal; and, a temperature calculating unit, receiving the first and the second processing signals and performing calculation to derive a temperature value.

Abstract: In a PWM signal generation method of a voltage regulator, an output sense signal, a first ramp signal and a second ramp signal are provided. A first time point of the first ramp signal crossing with the output sense signal is used to determine a start point of an ON-time of a PWM signal, and a second time point of the second ramp signal crossing with the output sense signal is used to determine an end point of the ON-time of the PWM signal. Moreover, the first ramp signal is reset to a reference voltage at the first time point and then maintained at the reference voltage, and further ramps down starting from the end point of the ON-time. The second ramp signal ramps up starting from the start point of the ON-time, and then is reset to a preset voltage at the second time point.

Abstract: A floating gate driver uses a single-end level shifter to translate a set signal and a reset signal induced by a rising edge and a falling edge of a switch signal to a common output terminal to generate an output voltage for a bistable circuit to generate a level shifted switch signal. Under control of a well transient detect signal asserted by detecting noise in the output voltage, a masking circuit between the single-end level shifter and the bistable circuit masks noise in the output voltage. This configuration has lower area penalty and better noise immunity.

Abstract: A power supply includes a first circuit, a second circuit, a feedback circuit and a controller. The first circuit has a first switch, and the second circuit has a second switch. The first circuit transforms an input voltage to a middle voltage, and the second circuit transforms the middle voltage to an output voltage. The feedback circuit electrically connects to the controller and the output voltage respectively. The controller includes a first sub-control unit and a second sub-control unit. The first sub-control unit electrically connects to the first switch and the second sub-control unit electrically connects to the second switch. The controller generates a compensation voltage signal for the first sub-control unit and the second sub-control unit to control the first switch and the second switch.

Abstract: A voltage converter circuit, includes: a power switch for generating a pulse-width-modulation (PWM) signal to drive a current load, wherein the PWM signal toggles between a first level and a second level; a sensing pin, receiving a first sensing signal when the PWM signal is at the first level, and receiving a second sensing signal when the PWM signal is at the second level; a parameter sampling and setting unit, having an input terminal coupling to the sensing pin, generating a default current or a default voltage on the sensing pin and sampling the second sensing signal to generate a sampling signal when the PWM signal is at the second level, and holding the sampling signal to set a parameter of the voltage converter circuit when the PWM signal is at the first level.

Abstract: A power converter includes a first conversion stage for converting an input voltage to a first output voltage and a second conversion stage for converting the first output voltage to a second output voltage. An error signal is generated according to a reference voltage and a feedback signal extracted from the second conversion stage, and a feed forward signal is generated from the error signal and injected into the first conversion stage to stabilize the first output voltage. The feedback signal is a function of the second output voltage and thus, the error signal varies with the second output voltage. As a result, the first output voltage will be stabilized when the second output voltage varies, due to the varied feed forward signal.

Abstract: A control circuit of a switching DC-DC power supply includes a feedback circuit detecting an output voltage of the power supply to generate a feedback signal, an error comparator detecting an error between the output voltage and a design value of the output voltage, a control logic circuit generating a control signal according to the error for regulating the output voltage, and an offset and delay cancellation circuit generating an offset adjust signal according to the feedback signal and a second reference voltage for adjusting an offset of the error comparator to pull the output voltage toward the design value.

Abstract: A high voltage half-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.

Abstract: LED dimming control circuit and method compensate LED current or LED average current by LED characteristics to improve dimming efficiency and performance. LED characteristic related look-up tables are stored to provide compensation values, and input LED current setting information is compensated by the compensation values to generate corrected LED current setting information for determining LED brightness.

Abstract: A feedback loop is used to optimize a zero current threshold for a switching regulator. After the low side power switch of the switching regulator turns off, the switching node state is monitored to adjust the zero current threshold in a real time and thus the low-side power switch is prevented from turning off too early or too late. Thereby the efficiency in green mode is optimized.

Abstract: A floating gate driver uses a single-end level shifter to translate a set signal and a reset signal induced by a rising edge and a falling edge of a switch signal to a common output terminal to generate an output voltage for a bistable circuit to generate a level shifted switch signal. Under control of a well transient detect signal asserted by detecting noise in the output voltage, a masking circuit between the single-end level shifter and the bistable circuit masks noise in the output voltage. This configuration has lower area penalty and better noise immunity.

Abstract: A bootstrap circuit includes: a charging voltage source; a charging diode, having an anode coupled to the charging voltage source; a high-voltage transistor, having a control terminal defined as a first connecting node and a channel coupled between a cathode of the charging diode and a bootstrap capacitor; a logic control circuit, having a first and a second logic outputs, and a logic input for receiving a charging command; a high-voltage control transistor, having a control terminal defined as a second connecting node and a channel coupled between charging voltage source and the first connecting node; a cut-off resistor, coupled between the first and the second connecting nodes; a charging control transistor, having a channel coupled between the second connecting node and a ground terminal, and a control terminal coupled to the second logic output; a control capacitor, coupled between the first connecting node and the first logic output.

Abstract: A switching power converting apparatus is capable of converting an input voltage to an output voltage, and includes a transformer, a primary side control module, and a secondary side control module. The secondary side control module utilizes voltage clamping techniques or current-drawing techniques to stop self-excited conversion from the input voltage to the output voltage when the output voltage is greater than a predetermined target voltage, or utilizes a non-self-excited conversion architecture.

Abstract: An exemplary method for improving voltage identification (VID) transient response is adapted to a voltage regulator and includes steps of: continuously sensing an inductor current of the voltage regulator to thereby output a current sense signal; during a steady state operation period, sampling the current sense signal to thereby obtain a sampling result for providing a droop control signal; after entering a VID transient period from the steady state operation period, holding the sampling result for providing the droop control signal; and taking the droop control signal as a consideration factor of producing a pulse width modulation signal to regulate an output voltage of the voltage regulator.

Abstract: An electrostatic transducer loudspeaker includes a filterless class-D amplifier to modulate an audio input signal to generate a modulated signal containing a PWM switching carrier component, and a transformer directly connected at an output side of the filterless class-D amplifier and directly connected at an input side of an electrostatic transducer, whereby the equivalent capacitance of the electrostatic transducer and the equivalent inductance of the transformer establish a resonance circuit to demodulate the modulated signal to generate an AC voltage to drive the electrostatic transducer.

Abstract: A reverse shunt regulator includes a MOSFET connected between a cathode and an anode, a switch and a current source serially connected between the cathode and the anode, and an error amplifier having a positive input node to receive an internal reference voltage, a negative input node connected to the reference electrode, and an output node connected to a control electrode of the MOSFET. When the voltage of the reference electrode is within a range, the larger the voltage of the reference electrode is, the less the current of the MOSFET is. Application of this reverse shunt regulator to a flyback converter for output feedback will reduce the power loss in a green mode of the flyback converter.

Abstract: A delta-sigma modulator includes: a loop filter for processing an analog input signal and a feedback signal to generate a filtered signal; a noise coupler operable to generate a noise coupled signal based on the filtered signal and the feedback signal; a quantizer for quantizing the noise coupled signal to generate a digital output signal; and a digital-to-analog converter converting the digital output signal to the feedback signal. The noise coupler includes an amplifier that has an inverting input terminal receiving a difference between the filtered signal and the feedback signal, and a non-inverting output terminal outputting the noise coupled signal, and a capacitor coupled between the inverting input terminal and the non-inverting output terminal of the amplifier.

Abstract: A power off delay circuit includes a switch connected between an external power input terminal and an internal power supply terminal, a capacitor connected to the internal power supply terminal, and a hysteresis comparator to switch the switch according to the voltages of the external power input terminal and the internal power supply terminal. During on-time of the switch, the external power input terminal is connected to the internal power supply terminal and the capacitor can be charged by the external power source. When the switch is off, the capacitor provides electric power for an internal circuit. Application of the power off delay circuit to an audio system may eliminate the turn-off pops of the audio system.

Abstract: For thermal compensation for an intrinsic element in a system, a circuit and method are proposed to predict the temperature variation caused by power loss of the intrinsic element, in addition to sense the external environment temperature variation of the intrinsic element, and thus sense the operational temperature of the intrinsic element more precisely.