| 摘要 |
The present invention provides an LED backlight drive circuit, which includes a first power supply module, an electrical inductor, a rectifier diode, a MOS transistor, an electrolytic capacitor, an LED light string, a voltage division module, a voltage comparator, a second power supply module, and an LED constant-current drive chip. The LED backlight drive circuit is arranged to include a voltage comparator in an external circuit of the LED constant-current drive chip to detect output voltage of the drive circuit so that high voltage, the voltage comparator is caused to supply a low voltage level to forcibly pull down a PWM dimming signal or an ENA enabling signal of the LED constant-current drive chip to achieve an over-voltage protection function and also enable removal of over-voltage protection module from a conventional LED constant-current drive chip. |
| 主权项 |
1. An LED (Light Emitting Diode) backlight drive circuit, comprising: a first power supply module, an electrical inductor, a rectifier diode, a MOS (Metal Oxide Semiconductor) transistor, an electrolytic capacitor, an LED light string, a voltage division module, a voltage comparator, a second power supply module, and an LED constant-current drive chip;
the electrical inductor having an end electrically connected to the first power supply module and an opposite end electrically connected to an end of the rectifier diode and the MOS transistor, the rectifier diode having an opposite end electrically connected to the electrolytic capacitor, the voltage division module, and the LED light string, the MOS transistor having an end electrically connected to the LED constant-current drive chip, the voltage division module being electrically connected to the voltage comparator and the second power supply module, the MOS transistor, the electrolytic capacitor, the voltage division module, and the LED light string being electrically connected to a grounding line; the LED constant-current drive chip comprising an ENA enabling signal pin and a PWM (Pulse Width Modulation) dimming signal pin, the voltage comparator comprising an output pin, the output pin being electrically connected to the ENA enabling signal pin or the PWM dimming signal pin. |
