Description

The SM8133B00B is a charge pump type white LED driver suitable for driving 1 to 6 backlight white LED connected in parallel and 1 flash white LED. It is designed with a 3.0V LDO (Low Dropout Regulator), making it ideal for camera-equipped cellular phones. The charge pump switches between ×1 to ×1.5 boost mode based on the LED drive current requirements, thus maximizing battery life. The device supports variations in LED forward-bias voltage drop (VF) by responding to the drive current of all the connected LED. It features a 7-channel LED drive current control circuit to control the drive current of each LED, with the 6 backlight channels divided into 2 groups for independent dimming and lighting control. The backlight grouping, backlight LED drive current and ON/OFF control, flash LED drive current and ON/OFF control, and LDO output ON/OFF control can all be set using a 3-wire serial interface data input. Additionally, the RESETB pin can be connected to the microcontroller supply for a system-wide shutdown function.

Specifications and features

• Noise reduction due to charge pump boost circuit
• Automatic charge pump switching to conserve power
• Drives 1 to 6 backlight white LED (30mA/ch at maximum setting)
• Drives a flash white LED (150mA at maximum setting)
• Backlight and flash white LED brightness adjustment
• Group settings for 2-group backlight lighting control
• 3-wire serial input interface for all setting and control
• 3.0V output LDO circuit built-in
• Shutdown function by RESETB pin
• Soft start circuit built-in
• Thermal protection circuit built-in
• Input voltage range:
  • No-load current (IOUT= 0mA): 2.7 to 4.6V
  • Load current (IOUT= 80mA): 3.0 to 4.6V
  • Load current (IOUT= 200mA): 3.3 to 4.6V
• Quiescent current:
  • LDO only: 0.3mA (typ)
  • Not-switching (×1.0 mode): 0.5mA (typ)
  • Switching (×1.5 mode): 2.5mA (typ)
• Standby current: 0.01µA (typ)
• Operating frequency: 750kHz (typ)
• Backlight LED current: 30mA/ch (typ)
• Flash LED current: 150mA (typ)
• All LED total maximum current: 200mA (typ)
• Backlight LED current matching (ILED= 30mA): ±3%
• Flash LED current accuracy (ILED= 150mA): ±5%
• LDO (Low Dropout Regulator) output voltage: 3.0V±2%
• Packages: 20-pin QFN WL-CSP (under development)

Application Scenarios

The SM8133B00B is commonly used in the following applications:

• Cellular phones
• Digital still cameras
• PDA
• Portable games

Comparison

• Supports driving 1 to 6 parallel backlight white LED and 1 flash white LED
• Extends battery life by switching between ×1 to ×1.5 boost mode based on LED drive current requirements
• Allows independent dimming and lighting control for the 6 backlight channels divided into 2 groups
• 3-wire serial interface data input for easy setting and control
• Built-in 3.0V LDO (Low Dropout Regulator)
• Shutdown function by RESETB pin for system-wide shutdown
• Includes soft start circuit and thermal protection circuit

• Package is currently under development