Please note: this product is being discontinued and is not recommended for new designs.
The SKYA21004 consists of a power management block
supplying LCD bias rails and a three-channel backlight driver.
The LCD bias power management block of the SKYA21004
includes a boost converter that supplies main analog voltage
(AVDD) of the panel, two charge-pump controllers supplying a
gate-on voltage (VGH), and a gate-off voltage (VGL) to the LCD
panel. The boost converter uses a 1.3-MHz fixed frequency to
generate AVDD voltage up to 14.5 V. Two charge-pump
controllers can generate up to +30 V and down to 30 V from the
charge-pump stages configured by diodes and capacitors. A
proprietary regulation algorithm can minimize the output ripple.
The backlight driver of the SKYA21004 integrates the boost
converter to drive the LED voltage up to 28 V. The switching
frequency is adjustable from 600 kHz to 2 MHz for system
integration flexibility, which optimizes the efficiency and controls
EMI. Three precision current sinks are programmable to drive LED
current up to 120 mA per string.
The backlight driver of the SKYA21004 supports Analog Pulse
Width Modulation (APWM) dimming, Direct Pulse Width
Modulation (DPWM) dimming, and analog dimming (through I2C).
In the DPWM dimming mode, the output waveform follows the
duty and the frequency of control input signal from the PWM pin.
In the APWM dimming mode, the LED current of each channel is
controlled by the input duty of PWM input signal, the I2C
programmed brightness level, and the external RISET resistor.
The PWM pin can accept the frequency range from 100 Hz to
25 kHz with 10-bit resolution of duty control and 8-bit resolution
of current control. When the PWM pin is not used, it needs to be
pulled high.
The SKYA21004 is available in a 7 mm 4 mm, 36-pin QFN package.