Abstract: A linear voltage regulator has a regulating transistor with a first channel electrode receiving an input voltage source and a second electrode providing an output voltage. A control electrode of the regulating transistor is controlled by an error amplifying circuit based on comparison between a feedback signal of the output voltage and a reference voltage. An event detecting circuit is coupled to the input voltage source for detecting occurrence of a transient in the input voltage source. In response to the detected transient event, an enable controlling circuit generates an enable signal for determining an effective operation time of a voltage clamping circuit. During such effective operation time, a potential difference between the first channel electrode and the control electrode is limited within a predetermined clamp voltage for preventing the regulating transistor from being dramatically changed in operation.

Abstract: Dual edge modulated charge pumping circuit has an output terminal, a charge pumping conversion circuit, and a dual edge modulated control circuit. The charge pumping conversion circuit has a first capacitor, a second capacitor, and a switch combination circuit. The second capacitor is coupled between the output terminal and a ground potential. The dual edge modulated control circuit controls the switch combination circuit such that the charge pumping conversion circuit operates with a first phase, a second phase, a third phase, and a fourth phase. During the first phase, a first electrode of the first capacitor is floated. During the second phase, the first capacitor is coupled between the ground potential and an input voltage. During the third phase, the first capacitor is coupled between the input voltage and the output terminal. During the fourth phase, the first electrode of the first capacitor is floated.

Abstract: A bias current compensation circuit for a differential input stage has a compensation current supplying circuit and a compensation selecting circuit. The compensation current supplying circuit generates a compensation current. The compensation selecting circuit is coupled between the compensation current supplying circuit and a first and a second input terminals of the differential input stage. When the first input terminal needs to be driven by a first bias current, the compensation selecting circuit determines to allow the compensation current to be applied to the first input terminal for serving as the first bias current. When the second input terminal needs to be driven by a second bias current, the compensation selecting circuit determines to allow the compensation current to be applied to the second input terminal for serving as the second bias current.

Abstract: A temperature measurement circuit has a current excitation circuit, a temperature calculation circuit, a calibration factor generator, and an analog-to-digital conversion circuit. The current excitation circuit supplies in sequence at least two currents to a thermal sensor. At least two output signals are correspondingly generated from the thermal sensor. In response to the at least two output signals, the temperature calculation circuit calculates an analog temperature signal representative of a temperature detected by the thermal sensor. The analog-to-digital conversion circuit converts the analog temperature signal into a digital signal based on a conversion reference level. The conversion reference level is shifted in accordance with a calibration value generated from the calibration factor generator.

Abstract: A rail-to-rail operational amplifier is provided with a high-side current adjusting circuit and a low-side current adjusting circuit. On a basis of a comparison between a first input voltage and a second input voltage, the high-side current adjusting circuit adjusts a high-side bias current. Under a condition that the first input voltage is smaller than the second input voltage, the high-side current adjusting circuit increases the high-side bias current when an absolute value of a difference between the first and the second voltages increases. On a basis of the comparison between the first and the second input voltages, the low-side current adjusting circuit adjusts a low-side bias current. Under a condition that the first input voltage is larger than the second input voltage, the low-side current adjusting circuit increases the low-side bias current when the absolute value of the difference between the first and the second voltages increases.

Abstract: A switching voltage regulator has a first switch, a second switch, and an inductor, which are coupled together to a switch node. A switch control system applies a drive signal for controlling the first and the second switches. A duty cycle detecting circuit detects a duty cycle of the drive signal. When the duty cycle is larger than a predetermined threshold, the duty cycle detecting circuit generates an over-threshold signal. When the duty cycle is smaller than the predetermined threshold, the duty cycle detecting circuit generates an under-threshold signal. In response to the over-threshold signal and the under-threshold signal, an oscillating signal adjusting circuit generates an adjusting current. An oscillating signal generating circuit generates and applies an oscillating signal to the switch control system. The oscillating signal has a period adjusted by the adjusting current.

Abstract: At first, a plurality of detection modes are applied in sequence to a brushless DC motor, such that with respect to each of the detection modes a composite magnetic field generated by a motor current flowing through motor coils points in a different direction. Then, each of peak values of the motor currents generated by the detection modes is compared with respect to one another so as to select, from the plurality of detection modes, one detection mode which generates a largest one of the peak values of the motor currents. An initial position of a rotor is determined on a basis of a direction of a composite magnetic field generated by the detection mode which generates the largest one of the peak values of the motor currents. Based on the initial position of the rotor, the brushless DC motor is driven to start rotating.

Abstract: A synchronous switching voltage converter has a first switch, a second switch, and an inductor, coupled together to a switch node. A reverse current preventing circuit has a fixed reference current source, a correcting circuit, a variable reference current generating circuit, and a comparing circuit. Based on a comparison between an inductor current and the fixed reference current source, the correcting circuit generates a correcting signal. The variable reference current generating circuit generates a variable reference current signal, which is adjusted in accordance with the correcting signal. Based on a comparison between the inductor current and the variable reference current signal, the comparing circuit applies a preventing signal to the second switch so as to turn off the second switch.

Abstract: A PFM control circuit generates a pulse control signal for controlling a switching regulator to convert an input voltage into an output voltage. The pulse control signal has a plurality of switch cycles, each of which consists of an ON-time and an OFF-time. The ON-time is applied to turn on a switching circuit of the switching regulator while the OFF-time is applied to turn off the switching circuit. A current detection signal is representative of a current flowing through an inductive device of the switching regulator. The ON-time is prolonged in accordance with an increase of a maximum of the current detection signal. A voltage detection signal is representative of the output voltage. The OFF-time is prolonged in accordance with a reduction of a falling rate of the voltage detection signal.

Abstract: Through operated alternately between a charging phase and a discharging phase, a charge pump converts an input voltage source into a drive voltage for being supplied to a light emitting diode. A current setting unit determines a reference current. A current regulating unit has a current regulating terminal and a feedback detecting terminal. The current regulating terminal is coupled to the light emitting diode so as to control a current flowing through the light emitting diode to be proportional to the reference current. The feedback detecting terminal provides a feedback signal representative of a current regulation characteristic voltage. Based on a difference between the feedback signal and a reference voltage source, an error amplifier generates an error signal. A variable resistance unit is coupled between the input voltage source and the charge pump for adjusting a variable resistance in response to the error signal.

Abstract: A switching amplifier includes a level shifting circuit for adjusting a voltage level of an original input signal to generate a first input signal and a second input signal. The first input signal is identical to the original input signal except for referring to a first reference level. The second input signal is identical to the original input signal except for referring to a second reference level. In response to the first input signal and an oscillating signal, a first control circuit generates a first width-limited PWM signal for controlling a first half-bridge switching circuit. In response to the second input signal and the oscillating signal, a second control circuit generates a second width-limited PWM signal for controlling a second half-bridge switching circuit.

Abstract: A switching amplifier includes a level shifting circuit for adjusting a voltage level of an original input signal to generate a first input signal and a second input signal. The first input signal is identical to the original input signal except for referring to a first reference level. The second input signal is identical to the original input signal except for referring to a second reference level. In response to the first input signal and an oscillating signal, a first control circuit generates a first width-limited PWM signal for controlling a first half-bridge switching circuit. In response to the second input signal and the oscillating signal, a second control circuit generates a second width-limited PWM signal for controlling a second half-bridge switching circuit.

Abstract: A multi-mode charge pump drive circuit has a multi-mode charge pump, a switch control circuit, a current regulation circuit, an error amplifier, a variable resistance unit, and a mode selection circuit. The multi-mode charge pump is operated with a plurality of modes, each of which provides a different multiplicative ratio for converting an input voltage source into a drive voltage. The switch control circuit applies a switch control signal to the multi-mode charge pump. The switch control signal has a slew rate of edge for determining a transition span of the interchange between charging and discharging phases. The mode selection circuit controls the multi-mode charge pump to selectively operate with one of the plurality of modes. When the mode selection circuit changes the mode of the multi-mode charge pump, the mode selection circuit applies a mode change signal to the switch control circuit so as to reduce the slew rate of edge.

Abstract: A voltage converting circuit has an output terminal for supplying an output current at an output voltage to a load. In response to a transient of the load, a current sinking circuit allows a current source to provide a sink current flowing from the output terminal of the voltage converting circuit into a ground potential. The sink current is finite and stable. When the output voltage decreases below a threshold voltage, the current sinking circuit allows the current source to keep providing the finite and stable sink current for an extension time, causing the output voltage to decrease from the threshold voltage to a regulated value.

Abstract: Through a plurality of consecutive frames, a display controller produces a multi-gradation image on a display device formed by a plurality of binary-state pixels in an array. The display controller includes an image memory for providing each of the pixels with gradation data. A waveform pattern selector outputs a waveform pattern selecting signal for causing a waveform pattern memory to provide any two adjacent pixels with two different sets of waveform pattern signals. The plurality of consecutive frames are operated at a fixed frame rate, which is set high enough for preventing visual disturbances.

Abstract: A first to an n-th current sources supply a first to an n-th charging currents, respectively. A sequence control circuit allows an x-th charging current of the first to the n-th charging currents to charge a capacitor for generating an x-th soft-start signal. The variable x is an integer and satisfies an inequality of n?x?1. Before a y-th charging current is allowed to charge the capacitor for generating a y-th soft-start signal, the sequence control circuit stops charging the capacitor by the x-th charging current and discharges the capacitor toward a ground potential. The variable y is an integer different from the variable x and satisfies an inequality of n?y?1.

Abstract: A switching circuit operates with a first operating state and a second operating state. During the first operating state, the switching circuit allows a switching current to linearly increase. During the second operating state, the switching circuit allows the switching current to linearly decrease. A control circuit is coupled to the switching circuit for controlling the switching circuit to operate with the first operating state or the second operating state. A setting circuit generates a threshold signal for the control circuit to ensure that during the first operating state the switching current linearly increases to become higher than or equal to a current value set by the threshold signal. Thereby, the switching current is prevented from linearly decreasing to reverse polarity during the second operating state.

Abstract: An input switching unit selectively couples a first terminal of an inductor with an input voltage and a ground potential. An output switching unit selectively couples a second terminal of the inductor with an output voltage and the ground potential. A first pulse generating circuit generates a first pulse signal with a first duty ratio, which is modulated in response to the output voltage. A second pulse generating circuit generates a second pulse signal with a second pulse signal with a second duty ratio, which is a constant larger than zero and smaller than one. When the first duty ratio is larger than a predetermined threshold duty ratio, a mode control circuit applies the first pulse signal to control one of the input switching unit and the output switching unit and applies the second pulse signal to control another of the input switching unit and the output switching unit.

Abstract: When a primary winding current increases to an upper limit determined by a reference voltage having a soft-start characteristic, a power switch is turned OFF. When a secondary winding current decreases to a lower limit determined by another predetermined reference voltage, the power switch is turned ON. A minimum ON-time limiting unit prevents the power switch from being turned OFF before a minimum ON-time expires. The minimum ON-time may be provided with a soft-start modulation. A minimum OFF-time limiting unit prevents the power switch from being turned ON before a minimum OFF-time expires. A maximum ON-time limiting unit prevents the power switch from still remaining ON after a maximum ON-time expires.

Abstract: A switching amplifier includes a level shifting circuit for adjusting a voltage level of an original input signal to generate a first input signal and a second input signal. The first input signal is identical to the original input signal except for referring to a first reference level. The second input signal is identical to the original input signal except for referring to a second reference level. In response to the first input signal and an oscillating signal, a first control circuit generates a first width-limited PWM signal for controlling a first half-bridge switching circuit. In response to the second input signal and the oscillating signal, a second control circuit generates a second width-limited PWM signal for controlling a second half-bridge switching circuit.