The iW7025 was developed by Dialog's Power Conversion Business Group (formerly iWatt Inc.) and extends Dialog's addressable market into the LCD TV backlighting power management space.
A key challenge for LED TV designers is how to easily reduce motion blur and deliver a high contrast ratio. With conventional LED drivers this requires complex calculations and algorithms to configure the LED current phases to optimally synchronize the LCD panel backlight to the video frame refresh rate. The iW7025's AnyMode dimming solves this issue by providing comprehensive, simple and flexible dimming options that improve LED TV picture quality and reduce design complexity. These dimming modes include high frequency pulse width modulation (PWM) up to 4kHz, scanning-mode PWM, configurable phase-shift, 8-bit analog, 13-bit local and hybrid dimming.
AnyMode dimming enables continuous PWM signals or burst PWM signals that are fully synchronized to the video frame at the same or higher frequency. The PWM duty cycle can be updated in each video frame and with user-configurable tail or head delays. This gives designers more options to reduce motion blur and improve the contrast ratio. A built-in phase-locked loop (PLL) further ensures jitter-free operation even with a noisy VSYNC signal.
The PWM dimming range of the iW7025 is 0% to 100%, with 13-bit resolution. Precise control of the PWM output position and the PWM duty cycle offer the flexibility to support both patterned retarder (PR) and shutter glass (SG) 3D technologies, while hybrid dimming lets users mix PWM and analog dimming modes to maximize system efficiency. Phase-shift dimming allows the use of smaller output capacitors, eliminating audible noise, improving electromagnetic interference (EMI), and lowering cost.
(Jim Evans)
