A power converting apparatus includes a power input terminal, a power filter, a first output terminal, a converting transformer and a second output terminal. The power input terminal receives a first power signal from exterior. The power filter is electrically connected with the power input terminal for receiving the first power signal and generating a second power signal according to the first po...

An exemplary power supply control circuit (200) includes a first port (201), a second port (202), a third port (203), a controllable switch (280), and a control circuit (270). The first and second ports are configured to receive a power supply voltage signal. The second and third ports are configured to output the power supply voltage signal to a load circuit. The controllable switch includes a co...

A highly stable current-mode resonant inverter circuit by detecting resonance current in the secondary side circuit. A current-mode resonant inverter circuit comprises a step-up transformer; a side of a secondary winding of the step-up transformer composes a resonant circuit between leakage inductance of the step-up transformer secondary winding and a capacitive component present in the secondary...

An electrostatic holding device ( 100 ) in which an electrode group ( 103 ) having a plurality of electrodes covered with an insulating material ( 102 ) is used as a holding surface applies predetermined voltage to the electrode group ( 103 ) to hold a holding object ( 104 ) by an electrostatic force with a contact state or with a floating non-contact state. The electrostatic holding includes an i...

A power cutter, an oscillator, a counter, a S-R latch, and a Hall bias are further disposed inside a DC motor driving circuit so that current consumption of the DC motor driving circuit is reduced significantly under a standby mode. When the counter detects that a received pulse width modulation signal stays at a low electrical level over a predetermined time, the counter triggers the S-R latch so...

A fan system includes a driving device, a speed detecting device and a logic device. The driving device generates a speed detecting signal and a predetermined alarm signal. The speed detecting device, which is electrically connected with the driving device, receives the speed detecting signal, and generates a low speed signal when the speed detecting signal is lower than a reference signal. The lo...

A fan control device receives a first power signal and a second power signal to drive a fan. The first power signal is input into the fan control device earlier than the second power signal. The fan control device includes a driving circuit, a revolution output circuit and a noise limiting circuit. The driving circuit receives the second power signal to drive the fan to rotate, and senses a revolu...

An I/O output circuit is disclosed for interfacing a first system operating at a first voltage with a second system operating at a second voltage higher than the first voltage. The I/O output circuit includes an output stage module having one or more PMOS transistors and one or more NMOS transistors for coupling with the second system. A switch module is coupled to the output stage module for sele...

A layout of a power device is provided. The layout includes a substrate, a unit array, a plurality of first, second, third and fourth signal paths, and a first, second, third and fourth port. The unit array with a plurality of rows is disposed on the substrate. Each row of the unit array includes a plurality of units. The first and second signal paths on the substrate are disposed on a first side ...

A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI. In the filterless power amplifier, differential outputs for driving load impedance are corrected based on input audio signals by the error amplifier. Reference wave generators generate reference waves. Comparators are responsive to the reference waves and the input audio signal. Operation state...

The present invention discloses a frequency-hopping carrier generator, which comprises a current source, a ramp generator and a switch power amplifier. The current source generates a first current; the first current is output to the ramp generator. The output of the ramp generator is coupled to a capacitor to generate a ramp voltage. The ramp voltage is connected to a voltage detection/direction c...

A CMOS class A/B output stage provides the advantages of high speed operation, low supply voltage requirements, and low quiescent current draw, resulting from the use of subthreshold biasing of the output driver transistors. The architecture of the output stage makes it particularly suitable for use in operational amplifiers in power demanding applications, such as portable instruments, smoke dete...

The present invention provides a voltage amplifier, which comprises a first load circuit, a second load circuit cascaded with the first load circuit, a first differential pair circuit and a second differential pair circuit. The first differential pair circuit receives an input voltage, outputs a consistent current, electrically connected to the first load circuit in a folded manner, and commonly r...

The present invention provides a differential amplifier with a plurality of input pairs. The differential amplifier not only includes a differential amplifier with a single input pair but also includes a pair of transistors and a current source to provide the input signals of an extra input pair. The pair of transistors and the differential amplifier with a single input pair share a same load unit...

A preamplifier includes cascade-connected amplifying circuits, and at least one of the cascade-connected amplifying circuits includes a differential switch pair circuit, a comparator and energy storing elements. The differential switch pair circuit has a pair of differential inputs and a pair of differential outputs. The comparator outputs a comparison signal by comparing the differential outputs....

The present invention provides a method and apparatus for supplying power to a load at a plurality of different power levels. The method includes changing between high and low power outputs of the power amplifier when amplifying a signal having a common modulation format. A different bias is applied to the power amplifier at the low power output than the bias applied to the power amplifier at the ...

The present invention discloses a circuit for eliminating speaker crackle during turning on or off a power amplifier and a method for the same, particularly to a circuit and method, wherein an input capacitor is used to pre-charge an output capacitor to reduce speaker crackle to an inaudible level during turning on or off a power amplifier. The present invention has a low cost and a simplified des...

A surface acoustic wave (SAW) bio-chip is designed with signal processing circuits. The chip can achieve precise measurements or detection quantitatively via the difference between the experiment-control mode, and followed by amplification and filtering of the signal processing circuits. By changing the designs of the substrate, quantitative detection toward different analyses can be achievable.

A status indicator and status indicating method are provided to indicate multi-working statuses of an electronic device with a single status indicator. The status indicator includes an MCU ( 10, 10 '), and an LED circuit. The MCU includes a CPU ( 101 ), a ROM ( 103 ), a RAM ( 105 ), a counter ( 107, 107 ') and an output port ( 111, 111 '). In a first embodiment, the MCU further includes a PWM regi...

The invention provides voltage level shifters comprising a transistor having a source coupling an input signal, a impedance module coupling the drain of the transistor to a voltage source, and a bias circuit generating a bias voltage to bias the transistor. The input signal may be at a first or a second voltage level. When the input signal is at the first voltage level, the transistor is turned on...