High-precision LCD screen backlight driver chip-OCP81781

     In this era where visuals reign supreme, screens have become an indispensable part of our lives. From smartphones to tablets, from laptops to televisions, crisp and vivid image quality is key to achieving an optimal user experience.

     In today's market, display technologies are primarily dominated by OLED and LCD screens. LCD displays, owing to their cost-effectiveness and long service life, continue to hold a significant share of the consumer electronics market. For LCD backlight driver chips in the smartphone market, the primary development focus is to achieve a wider brightness range, enabling these chips to operate effectively in both dimmer and brighter environments. The OCP81781 is specifically designed for this purpose, supporting PWM dimming from 0.2% to 100% of the maximum brightness. Moreover, at the lowest brightness level of 0.2%, it ensures consistent feedback voltage across the product range, outperforming a wide array of competing products on the market.

OCP81781 Application Scenarios

     The OCP81781 is a boost converter with a built-in 40 V rated integrated switching field-effect transistor, designed for series driving of LEDs. The boost converter operates at a fixed switching frequency of 1.1 MHz to reduce output ripple, improve conversion efficiency, and allow the use of compact external components. The default white LED current is set via an external sensing resistor RSET, with the feedback voltage regulated to 200 mV. During operation, a pulse-width modulation (PWM) signal can be applied to the EN pin; its duty cycle determines the feedback reference voltage. In PWM mode, the LED current does not undergo abrupt changes, thereby preventing audible noise from being generated on the output capacitor. To provide maximum protection, the device features an integrated open-circuit LED protection function; when the LED is open-circuited, the OCP81781 will shut down to prevent the output voltage from exceeding the IC's absolute maximum voltage rating. The OCP81781 is housed in a 2 mm × 2 mm DFN-6L package with a heat spreader.

Internal Block Diagram of OCP81781

     OCP81781 is commonly used in digital products featuring backlit LED displays, such as mobile phones, smartphones, and smart POS terminals.