Abstract: An apparatus and method for reducing the die area of a PWM controller include a protection circuit triggered by a fault index signal for counting, and the counting time is provided for a delay time required by fault verification. Therefore, fault detection circuits can be eliminated and the purpose of reducing the die area can be achieved.

Abstract: The present invention discloses a half-voltage headphone driver circuit, comprising: at least one operational amplifier providing an output to a headphone speaker, and a charge pump receiving a supply voltage (VDD), generating a positive half-voltage and a negative half-voltage (VDD/2 and ?VDD/2) based on the supply voltage, and supplying the positive half-voltage and negative half-voltage as high and low operation levels to the at least one operational amplifier.

Abstract: A flyback converter has a controller to switch a power switch so as to convert an input voltage to an output voltage for a load by monitoring an output voltage dependent signal and a current sensing signal derived from a current flowing through the power switch, a light-load efficiency improving apparatus monitors the load and a supply voltage provided for the controller to selectively clamp the output voltage dependent signal when the load is lower than a first threshold value and the supply voltage is lower than a second threshold value, so as to increase the supply voltage.

Abstract: The present invention discloses a charge pump start up circuit comprising: a start up transistor having one end which is electrically connected with a voltage supply source, and another end which is electrically connected to a voltage node; and a charge pump circuit having an input which is electrically connected with the voltage node, and an output which is electrically with the gate of the start up transistor.

Abstract: A frequency jittering control circuit wherein by means of the characteristics of a PLL whose input switches between different frequencies, the output frequency of the PLL swings between the different frequencies to achieve the desired frequency jittering.

Abstract: A linear voltage regulator comprises a transistor for converting a supply voltage to an output voltage. By directly monitoring the supply voltage and thereby rapidly responding when the supply voltage suffers a ripple, the linear voltage regulator enhances the stability of the output voltage.

Abstract: Time-sharing technique is used for power conversion to improve the thermal dissipation thereof. In a power supply arrangement to provide a supply voltage to a load, a plurality of linear regulators are so switched that each time only one of them is enabled to convert an input voltage to the supply voltage, thereby each of them suffering less thermal dissipation.

Abstract: For protecting a power system, two or three of over current, thermal and under voltage protection circuits are integrated as one protection circuit but operate independently, and one or more protection points thereof are adjusted dynamically in response to detected condition of the power system. Specifically, using voltage and current conditions in the power system to modify the over current protection and the thermal protection maximizes the performance of the power system and covers the process bias in the circuits.

Abstract: In a synchronized data communication on a one-wired bus, it transmits and receives a synchronizing signal that segments part of or all proportions of the data signal by use of three electrically distinguishable statuses for the identifier of the synchronizing signal and the logic states of the data signal to increase the endurance of frequency displacement and resist influences of the interference of external conditions, low quality of transmission medium, and limitation of transmission distance and make the reliability and correctness of the signal transmission improve substantially. It is also clearly illustrated the feasibility and simplicity for implementing the one-wired synchronized communication by a plurality of exemplary signal types and a transceiver circuitry.

Abstract: A pulse width modulator includes an amplifier module, a comparator module, and a filter module. The amplifier module receives a feedback voltage signal from a passive network, and generates first and second non-inverted voltage signals and first and second inverted voltage signals in response to the feedback voltage signal. The comparator module receives the first and second non-inverted voltage signals and the first and second inverted voltage signals, and provides first and second differential voltage signals corresponding to the first and second non-inverted voltage signals and the first and second inverted voltage signals. The filter module is coupled between the amplifier module and the comparator module, and is operable so as to attenuate high frequency components of the first and second non-inverted voltage signals. As such, the presence of noise in the feedback voltage signal does not affect differential operation of the comparator module.

Abstract: A pulse width modulator includes an amplifier module, a comparator module, and a filter module. The amplifier module receives a feedback voltage signal from a passive network, and generates first and second non-inverted voltage signals and first and second inverted voltage signals in response to the feedback voltage signal. The comparator module receives the first and second non-inverted voltage signals and the first and second inverted voltage signals, and provides first and second differential voltage signals corresponding to the first and second non-inverted voltage signals and the first and second inverted voltage signals. The filter module is coupled between the amplifier module and the comparator module, and is operable so as to attenuate high frequency components of the first and second non-inverted voltage signals. As such, the presence of noise in the feedback voltage signal does not affect differential operation of the comparator module.

Abstract: A conversion circuit for discriminating sourcing current and sinking current utilizes a complementary switch circuit to change the serial loop connected with the output load according to ON/OFF signals, so as to correspond to a sourcing current output and a sinking current output. The conversion circuit also employs a voltage emulation circuit to shift the feedback voltage of both sourcing and sinking current to a suitable positive range, so as to omit a negative power source design. The conversion circuit utilizes a switch control logic circuit to timely blank the partial compared result of the feedback voltage of sinking current to generate correct ON/OFF signals.

Abstract: A conversion circuit for discriminating sourcing current and sinking current utilizes a complementary switch circuit to change the serial loop connected with the output load according to ON/OFF signals, so as to correspond to a sourcing current output and a sinking current output. The conversion circuit also employs a voltage emulation circuit to shift the feedback voltage of both sourcing and sinking current to a suitable positive range, so as to omit a negative power source design. The conversion circuit utilizes a switch control logic circuit to timely blank the partial compared result of the feedback voltage of sinking current to generate correct ON/OFF signals.

Abstract: A programmable voltage supervisory circuit and method with minimum programming pins and low quiescent current is provided to monitor a supply voltage, by which only one programming pin can configure three voltage levels for the threshold voltage to be compared to the supply voltage. The programming pin is connected with a voltage select signal that is defined to be high, low or floating states each determines a setting voltage among three levels corresponding to the three threshold voltages, respectively, by a voltage select circuit. A sample/hold circuit in combination with a switch arrangement is further connected to the voltage select circuit such that the programmable voltage supervisory circuit is only operationable during the duty of a clock and thereby to reduce the power consumption thereof by squeezing the duty.

Abstract: A switching regulator with improved load transient efficiency comprises an output stage to generate an output voltage, a pulse width modulation circuit to generate a pulse width modulation signal, a constant ON-time circuit to generate an ON-time signal in accordance with the pulse width modulation signal to drive the output stage, and a masking apparatus to mask the ON-time signal by the pulse width modulation signal to thereby drive the output stage during load transient. During load transient, the masking apparatus reduces the switching times of the output stage to thereby reduce the switching loss and thus improve the efficiency of the regulator.

Abstract: An inductor equivalent circuit is disclosed. The circuit comprises a reference current source, a first current mirror, a second current mirror, two operational amplifiers OP1 and OP2, a capacitor, a first transistor, a second transistor, a mirror resistor set, and a bypass current source in parallel with the capacitor. An input signal is through OP1 and second transistor to control the reference current source. The first mirror current is then feed-back a signal to the first transistor through an OP2. The current signal makes the drain current of the first transistor lags the input voltage signal by 90° due to the capacitor coupled with the first mirror current source.

Abstract: A resistance adjustable of resistance mirror circuit having a master resistor R0, a reference current source terminal providing a current value I0 through the master resistor R0 to ground; a first transistor; a current mirror source terminal providing a current value n I0, through the first transistor to ground; an operational amplifier having a positive terminal connecting to a drain of the first transistor, a negative terminal connecting to the other terminal of the master resistor R0, and an output terminal connecting to a gate of the first transistor; a mirror resistor set composed of a plurality of transistors in parallel each other and having their source electrode connecting to ground. Each transistor of the mirror resistor set has a ratio of channel width over channel length being m-fold of that of the first transistor, where m, n is any positive numbers.

Abstract: A programmable voltage supervisory circuit and method with minimum programming pins and low quiescent current is provided to monitor a supply voltage, by which only one programming pin can configure three voltage levels for the threshold voltage to be compared to the supply voltage. The programming pin is connected with a voltage select signal that is defined to be high, low or floating states each determines a setting voltage among three levels corresponding to the three threshold voltages, respectively, by a voltage select circuit. A sample/hold circuit in combination with a switch arrangement is further connected to the voltage select circuit such that the programmable voltage supervisory circuit is only operationable during the duty of a clock and thereby to reduce the power consumption thereof by squeezing the duty.

Abstract: In a trimmer method and device, a reference signal of a target circuit is compared with a test signal, and a binary count output is generated according to result of the comparison. Thereafter, according to logic states of bits of the binary count output, electrical conduction through passive components that are coupled to the target circuit and that correspond respectively to the bits of the binary count output are selectively enabled and disabled so as to adjust the reference signal. The above steps are repeated by varying the binary count output until the reference signal approximates the test signal. Thereafter, fuses coupled to the passive components are melted selectively in a single fuse-melting operation so as to maintain the enabled and disabled states of electrical conduction through the passive components in order to set the reference signal to be approximate to the test signal.

Abstract: In a trimmer method and device, a reference signal of a target circuit is compared with a test signal, and a binary count output is generated according to result of the comparison. Thereafter, according to logic states of bits of the binary count output, electrical conduction through passive components that are coupled to the target circuit and that correspond respectively to the bits of the binary count output are selectively enabled and disabled so as to adjust the reference signal. The above steps are repeated by varying the binary count output until the reference signal approximates the test signal. Thereafter, fuses coupled to the passive components are melted selectively in a single fuse-melting operation so as to maintain the enabled and disabled states of electrical conduction through the passive components in order to set the reference signal to be approximate to the test signal.