| 摘要 |
A power on circuit is connected between a video graphics array (VGA) connector of a display and a super input output (SIO) chip of a motherboard. The power on circuit includes first to fourth electronic switches and a timer. When a power button of the display is pressed, a serial data line pin of the VGA connector outputs a high level signal to turn on the first electronic switch, the second electronic switch is turned on, the fourth electronic switch is turned on, and the timer outputs a periodic pulse signal. When the pulse signal outputted from the timer is at a high level, the third electronic switch is turned on, the SIO chip receives a low level signal from the fourth and third electronic switches, and the motherboard is turned on. |
| 主权项 |
1. A power on circuit connected between a video graphics array (VGA) connector of a display and a super input output (SIO) chip of a motherboard, the power on circuit comprising:
a first capacitor; a first resistor, a second resistor, and a third resistor; a first electronic switch comprising a first terminal connected to a serial data line (SDA) pin of the VGA connector, a second terminal connected to a power supply through a first resistor, and a third terminal grounded;
a second electronic switch comprising a first terminal connected to the second terminal of the first electronic switch, a second terminal connected to the power supply, and a third terminal;a timer comprising a power pin connected to the third terminal of the second electronic switch, a trigger pin connected to the third terminal of the second electronic switch through the second resistor and the third resistor in that order, a reset pin connected to the power pin, a control pin grounded through the first capacitor, a threshold pin connected to the trigger pin, a discharge pin connected to a node between the second resistor and the third resistor, and an output pin;a third electronic switch comprising a first terminal connected to the output pin of the timer, a second terminal connected to the SIO chip, and a third terminal; anda fourth electronic switch comprising a first terminal connected to the third terminal of the second electronic switch, a second terminal connected to the third terminal of the third electronic switch, and a third terminal grounded;wherein in response to a power button of the display being pressed to turn on the display, the SDA pin of the VGA connector outputs a high level signal, the first electronic switch is turned on, the second electronic switch is turned on, the fourth electronic switch is turned on, the output pin of the timer outputs a periodic pulse signal; andwherein in response to the pulse signal outputted from the output pin of the timer being at a high level, the third electronic switch is turned on, the SIO chip receives a low level signal from the fourth and third electronic switches, the motherboard is turned on. |
