Abstract: A power sequence circuit includes a control circuit and a plurality of output circuits. The control circuit provides a plurality of power-on signals and a plurality of power-off signals according to a power-on sequence and a power-off sequence. Each of the output circuits provides an output voltage when receiving a corresponding one of the power-on signals, and stops providing the output voltage when receiving a corresponding one of the power-off signals. The power sequence circuit controls the output voltages by the power-on sequence and the power-off sequence.

Abstract: A power supply test device includes a function generator, a loading circuit, a current detection circuit, and a controller. The function generator outputs a square-wave signal to the loading circuit. The loading circuit is electronically connected to a power supply, the loading circuit regulates an output current of the power supply according to the square-wave signal. The current detection circuit cooperates with the controller in detecting a slope of the output current. The controller compares the detected slope with a preset value, and regulates the square-wave signal according to the comparison to regulate the slope of the output current.

Abstract: A ground test circuit for a power supply unit includes a sampling circuit, a converting circuit, a processing circuit, and a switch circuit. The sampling circuit detects a voltage difference between a first ground terminal and a second ground terminal. The converting circuit converts the voltage difference to a digital value. The processing circuit compares the digital value to a predetermined value. As long as the digital value is smaller than the predetermined value, the switch circuit allows an external power source to be connected to the power supply unit. Thereby, the ground test circuit controls the connection between the external power source and the power supply unit according to the result of comparison of values done by the processing circuit.

Abstract: A measurement card includes a circuit board, an edge connector on a bottom edge of the circuit board, a port arranged on the circuit board, and a single-pole double-throw switch for connecting the port to either a first or a second pin of the edge connector to tests the VDDQ and VTT outputs of a memory slot.

Abstract: A buck converter includes a first electrical switch and a second electrical switch connected in series, a PWM module coupled to the gate of the first electrical switch through a first adjustable resistance module and coupled to the gate of the second electrical switch through a second adjustable resistance module, a filter circuit coupled between the connecting node of the two different electrical switches and an output node, and a control module for adjusting values of the first adjustable resistance module and the second adjustable resistance module and acquiring a voltage value from the connecting node.

Abstract: A keyboard includes a fingerprint input unit, a storage unit, a switch unit, and a control unit. The fingerprint input unit receives fingerprint information of a user. The storage unit stores a fingerprint model. The control unit is connected to the fingerprint input unit, the storage unit, and the switch unit. The control unit receives the fingerprint information of the user from the fingerprint input unit and compares the received fingerprint information with the fingerprint model stored in the storage unit. If the received fingerprint information is consistent with the fingerprint model, the control unit controls the switch unit to be turned on, to output a control signal to power on a computer connected to the keyboard.

Abstract: A power supply circuit for a CPU (central processing unit) includes a CPU, a power supply, a plurality of voltage adjustment modules, a pulse width modulator, a plurality of resistivity selection modules, and a module management unit. The resistivity selection module includes an electronic switch, a first resistor, a second resistor, a third resistor, and a fourth resistor. When the CPU operates abnormally, the power supply circuit utilizes the resistors in the resistivity selection module as voltage dividers, thereby restricting MOSFET or other components to operate in a normal voltage range.

Abstract: An apparatus tests currents from a plurality of power ports of a power supply unit (PSU), to test minimum value of the currents. The apparatus includes a connector, a controller, a time sequence detection circuit, and a plurality of load circuits. The time sequence detection circuit detects a start time-sequence of the ports of the PSU. Each load circuit is electronically connected to a power port of the PSU. The controller activates and applies each load circuit to a power port of the PSU according the start time-sequence of the ports of the PSU, controls a current-draw of each load circuit until the PSU works in a normal state, and displays the established minimum output current when the PSU works in the normal state.

Abstract: A power supply circuit includes a pulse width modulation (PWM) chip, a number of phase circuits, a voltage output end, and a spike suppression circuit. The spike suppression circuit is connected to each of the phase circuits and the voltage output end. The PWM chip controls all of the phase circuits to alternately output power supply voltages according to a predetermined sequence. The spike suppression circuit receives the power supply voltages, and filters out voltage spikes in the power supply voltages, thereby outputting steady voltages to the voltage output end.

Abstract: A temperature detecting apparatus for adjusting direction of airflow from a fan according to thermal status in an electronic device, includes a detection module, a control module, and a driver module. The detection module detects temperatures of a plurality of position coordinates in the electronic device and converts the detected temperatures and the plurality of position coordinates corresponding to the detected temperatures to first voltage signals. The control module receives the first voltage signals and compares the temperatures of corresponding position coordinates to output a position coordinate of the greatest temperature according to the first voltage signals. The driver module receives the position coordinate of the greatest temperature and directs airflow towards a position having the greatest temperature.

Abstract: A minimum output current adapting circuit draws currents from a plurality of power ports of a power supply unit (PSU). The current adapting circuit includes a plurality of current adapting units and a control unit. Each current adapting unit is electronically connected to one of the power ports. Each current adapting unit is configured to increase an output current of the power port, to facilitate the output current of the power port to be greater than a request minimum output current of the power port. The control unit is electronically connected to the PSU and a processor powered by the PSU, the control unit is configured to activate each current adapting unit when the PSU starts to work, and inactivate each current adapting unit after the processor is powered on and works in a normal state.

Abstract: A driving circuit includes a switching circuit, an acquiring circuit, an amplifying circuit, and an adjusting circuit. The switching circuit includes a driving chip and a switching unit. The switching unit is connected between a power source and a load, the driving chip is configured for controlling the connection and disconnection of the switching unit. The acquiring circuit is connected between the switching unit and the load, and is configured for providing a feedback to the amplifying circuit. The amplifying circuit includes two amplifying input terminals connected to two terminals of the acquiring circuit and an amplifying output terminal outputting an amplified voltage. The adjusting circuit is connected to the amplifying output terminal and is configured for outputting different control voltages to the driving chip according to the amplified voltage. The driving chip outputs different driving voltages to the switching unit according to the control voltages.

Abstract: A device that tests an output impedance of a voltage regulator module (VRM) includes a controller, a current regulating circuit, a voltage sampling circuit, and a current sampling circuit. The voltage sampling circuit samples an instantaneous alternating output voltage of the VRM, and outputs the instantaneous alternating output voltage to the controller. The current sampling circuit cooperates with the controller in sampling the instantaneous output current of the VRM. The controller controls the current regulating circuit to regulate the instantaneous output current of the VRM until the instantaneous alternating output voltage is about equal to a predetermined reference voltage, and calculates an output impedance of the VRM according to the instantaneous alternating output voltage and instantaneous output current when the instantaneous alternating output voltage is about equal to the predetermined reference voltage.

Abstract: A device for testing capacitive loads of a power supply includes a controller, a power supply switching circuit, a capacitive load switching circuit, and a current sampling circuit. The power supply switching circuit selects one of output voltages of the power supply to be electronically connected to the capacitive load switching circuit and the current sampling circuit. The current sampling circuit samples an output current of one output of the power supply selected by the controller. The controller turns on and off switches of the capacitive load switching circuit for matching an output current of the power supply with a reference current until the output current equals to the reference current. The controller outputs a total magnitude of the capacitive loads.

Abstract: A resistance determining system and method for a protection circuit, includes a resistance determining unit. The resistance determining unit interconnects a microcontroller and a digital resistor, where the microcontroller has first setting voltage corresponding to a first voltage threshold for activating the protection circuit, and the microcontroller is capable of receiving and converting a first external voltage input to the protection circuit to be a first converted voltage. The digital resistor includes a first variable resistor having two terminals connected to the respective first terminal and the second terminal. The microcontroller adjusts a resistance of the first variable resistor to be a first threshold resistance if the first converted voltage is substantially equal to the first voltage threshold, and the first resistance is determined to be substantially equal to the first threshold resistance.

Abstract: A power supply control circuit includes a main controller, a current detection unit electronically connected to the main controller, and a mode switch unit electronically connected to the main controller. The current detection unit cooperates with the main controller in detecting a value of an output current of a power supply circuit. The main controller determines whether the power supply circuit is operating in a discontinuous conduction mode or in a continuous conduction mode according to the value of the output current of the power supply circuit, and controls the mode switch unit to switch the power supply circuit to the continuous conduction mode when the power supply circuit operates in the discontinuous conduction mode.

Abstract: A snubber circuit for decreasing a voltage spike of a buck converter includes a resistor unit, a capacitor unit, a detecting unit, and a control unit. The resistor unit provides multiple groups of resistance values. The capacitor unit provides multiple groups of capacitance values. The detecting unit detects voltage spikes of the buck converter corresponding to each group of resistance values and capacitance values. The control unit selects each group of resistance and capacitance to respectively connect to the buck converter and determines a group of resistance and capacitance corresponding to a lowest voltage spike by comparing the detected voltage spikes with each other.

Abstract: An RC test circuit includes an RC circuit, a digital rheostat, a control chip, and an oscillograph. The RC circuit includes a plurality of positive terminals and a plurality of negative terminals. The digital rheostat includes a plurality of rheostats each including a sliding terminal and a fixed terminal. The sliding terminals are correspondingly connected to the positive terminals while the fixed terminals are correspondingly connected to the negative terminals. The control chip is connected to the digital rheostat, and configured for controlling the digital rheostat to change the resistance of each rheostat. The oscillograph is connected to the RC circuit for displaying a waveform of the RC circuit.

Abstract: A protocol resolution device electrically connected to a central processing unit (CPU) includes a signal controller to receive communication protocol from the CPU, a signal input module, and display module. The signal input module provides an electrical signal to the signal controller. The signal controller decodes the communication protocol from the CPU and stores the decoded communication protocol, the signal controller selectively accesses and calls up the decoded communication protocol according to the electrical signal, and transmits the decoded communication protocol to the display module for display.

Abstract: A power supply conversion circuit includes a PWM chip and many sub-circuits. Each sub-circuit includes an inductor, a first capacitor connected to ground, a first resistor connected in series with the first capacitor to form a branch parallel to the inductor, a differential pair having a first differential signal trace and a second differential signal trace, a second resistor, and a second capacitor. The first trace is connected between the connection of the first resistor and the first capacitor and the PWM chip. The second resistor is connected between the connection of the first resistor and the inductor and the second capacitor. The second trace is connected between the connection of the second resistor and the second capacitor and the PWM chip. The ratios of the capacitances of each two second capacitors are the same as that of the lengths of the traces of each two corresponding differential pairs.