SLUSCZ1 May 2017 TPS92518-Q1
PRODUCTION DATA.
The TPS92518-Q1 is a Dual Channel Buck LED controller with SPI Interface. Quasi-hysteretic operation allows a high control bandwidth and is ideal for Shunt FET and Matrix applications (series LED switched network). Internal DACs control the high-side differential peak current sense threshold, the peak-to-peak ripple (off-time) and the maximum off-time.
The high-side differential peak current sense threshold trip voltage is set via a 10:1 divider. The divider allows a lower sense voltage for improved efficiency while still allowing a practical control voltage. The device uses a controlled off-time (COFT) architecture to allow the converter to operate in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) with no external control loop compensation, and provides an inherent cycle-by-cycle current limit because of the peak current detection each cycle. Once an off-time (us·V) target is digitally programmed, analog circuitry adjusts the off-time to maintain a constant peak-to-peak ripple. Since the peak and ripple are fixed, regulation is maintained. The programmable off-time also controls the switching frequency target.
The digitally controlled analog peak current sense threshold allows analog dimming of the LED current over the full output range. The PWM dimming input allows for high-frequency PWM dimming control requiring no external components. An internal configurable maximum off-timer allows for easy implementation of external shunt FET dimming. Refer to shunt FET dimming information.This simple regulator contains all the features necessary to implement a high-efficiency, versatile, digitally controlled, high-performance LED driver.