摘要:
An exemplary backlight control circuit (200) includes two load circuits (210), a pulse width modulation integrated circuit (PWM IC) (250) having a current sampling pin (251), a switching circuit (270), a first input circuit (230) and a second input circuit (240) including an input resistor. Each load circuit includes a backlight (211, 221) and an output end (212, 222). The first input circuit includes a diode (231), a resistor (232), a capacitor (233) and a voltage division resistor (234). A negative terminal of the diode is connected to ground via the resistor and the capacitor respectively, and is connected to the switching circuit. A positive terminal of the diode is connected to one of the output end of the load circuits. The other one of the output ends of the load circuits is connected to the current sampling pin via the input resistor.
摘要:
An exemplary backlight control circuit (200) includes two load circuits (210), a pulse width modulation integrated circuit (PWM IC) (250) having a current sampling pin (251), a switching circuit (270), a first input circuit (230) and a second input circuit (240) including an input resistor. Each load circuit includes a backlight (211, 221) and an output end (212, 222). The first input circuit includes a diode (231), a resistor (232), a capacitor (233) and a voltage division resistor (234). A negative terminal of the diode is connected to ground via the resistor and the capacitor respectively, and is connected to the switching circuit. A positive terminal of the diode is connected to one of the output end of the load circuits. The other one of the output ends of the load circuits is connected to the current sampling pin via the input resistor.
摘要:
A drive circuit of a computer system is for driving a mode indicator. The computer system includes a first port and a second port. The mode indicator includes a first receiving end and a second receiving end. The drive circuit includes a first input end connected to the first port, a second input end connected to the second port, a first output end connected to the first receiving end, a second output end connected to the second receiving end. A power supply is connected to the first input end and the second input end via a first resistor and a second resistor respectively. The mode indicator is dichromatic and has two LEDs emitting non-matching colored light.
摘要:
An exemplary power switching circuit (20) includes a control signal input terminal (210); an output terminal (220); direct current (DC) power supply (230); a first transistor (250) including a control electrode connected to the control signal input terminal, a first current conducting electrode, and a grounded second current conducting electrode; a second transistor (260) including a control electrode connected to first current conducting electrode of the first transistor via a discharging resistor (264) and a diode (266) respectively and connected to the DC power supply via a discharging capacitor (265), a first current conducting electrode connected to the DC power supply, and a second current conducting electrode connected to the output terminal; and a third transistor (270) including a control electrode connected to first current conducting electrode of the first transistor, a first current conducting electrode connected to the output terminal, and a second grounded current conducting electrode.
摘要:
An exemplary power switching circuit (20) includes a control signal input terminal (210) which is configured for receiving a control signal; an output terminal (220) configured to be connected to a load circuit with capacitance; a direct current (DC) power supply (230); a first switching transistor (240) including a control electrode connected to the control signal input terminal, a first current conducting electrode, and a grounded second current conducting electrode; a second switching transistor (250) including a control electrode connected to the first current conducting electrode of the first switching transistor, a first current conducting electrode connected to the DC power supply, and a second current conducting electrode connected to the output terminal; and a third switching transistor (260) including a control electrode connected to the control signal input terminal, a first current conducting electrode connected to the output terminal, and a grounded second current conducting electrode.
摘要:
A drive circuit of a computer system is for driving a mode indicator. The computer system includes a first port and a second port. The mode indicator includes a first receiving end and a second receiving end. The drive circuit includes a first input end connected to the first port, a second input end connected to the second port, a first output end connected to the first receiving end, a second output end connected to the second receiving end. A power supply is connected to the first input end and the second input end via a first resistor and a second resistor respectively. The mode indicator is dichromatic and has two LEDs emitting non-matching colored light.
摘要:
An exemplary power switching circuit (20) includes a control signal input terminal (210); an output terminal (220); direct current (DC) power supply (230); a first transistor (250) including a control electrode connected to the control signal input terminal, a first current conducting electrode, and a grounded second current conducting electrode; a second transistor (260) including a control electrode connected to first current conducting electrode of the first transistor via a discharging resistor (264) and a diode (266) respectively and connected to the DC power supply via a discharging capacitor (265), a first current conducting electrode connected to the DC power supply, and a second current conducting electrode connected to the output terminal; and a third transistor (270) including a control electrode connected to first current conducting electrode of the first transistor, a first current conducting electrode connected to the output terminal, and a second grounded current conducting electrode.
摘要:
A drive circuit of a computer system is for driving a mode indicator. The computer system includes a first port and a second port. The mode indicator includes a first receiving end and a second receiving end. The drive circuit includes a first input end connected to the first port, a second input end connected to the second port, a first output end connected to the first receiving end, a second output end connected to the second receiving end, a power supply, a first transistor connected between the first input end and the power supply, and a second transistor connected between the second input end and the power supply. Collectors of the first and second transistors are separately connected to the first and second output ends. The mode indicator is dichromatic and has two LEDs emitting non-matching colored light.
摘要:
An exemplary power supply switching circuit (200) includes a first input (210) for receiving a first signal, a second input (220) for receiving a second signal, a voltage regulating circuit (240), and a signal switching circuit (250). The voltage regulating circuit includes semiconductor elements (241) electrically coupled in series. The signal switching circuit includes a first input terminal (253), a second input terminal (254), and an output terminal (255). The first input is electrically coupled to the first input terminal via the first voltage regulating circuit, the second input is electrically coupled to the second input terminal, and the output terminal is configured to be an output of the power supply switching circuit. The first voltage regulating circuit regulates the first signal via the voltage drops of the first semiconductor elements. A flat panel display using the power supply switching circuit is also provided.
摘要:
An exemplary voltage stabilizing circuit (2) includes a voltage input port (20), a voltage output port (21), a first transistor (22), a constant current circuit (23), and a feedback control circuit (24). The first transistor has a first base (221), a first emitter (222) connected to the output port, and a first collector (223) connected to the input port. The feedback control circuit has a resistor (244), a branch circuit (245-247), a voltage stabilizing unit (242), and a second transistor (241). The second transistor has a second emitter (2412) connected to ground via the voltage stabilizing unit and connected to the output port, a second collector (2413) connected to the first base of the first transistor, and a second base (2411) connected to the branch circuit. The constant current circuit provides current to the first base of the first transistor and the second collector of the second transistor.