The TPS92640 and TPS92641 devices are high-voltage, synchronous NFET controllers for buck-current regulators. Output current regulation is based on valley current-mode operation using a controlled on-time architecture. This control method eases the design of loop compensation while maintaining nearly constant switching frequency. The TPS92640 and TPS92641 devices include a high-voltage start-up regulator that operates over a wide input range of 7 V to 85 V. The PWM controller is designed for high speed capability, including an oscillator frequency range up to 1 MHz. The deadtime between high side and low side gate driver is optimized to provide very high efficiency over a wide input operating voltage and output power range. The TPS92640 and TPS92641 devices accept both analog and PWM input signals, resulting in exceptional dimming control range. Linear response characteristics between input command and LED current is achieved with true zero LED current using low off-set error amplifier and proprietary PWM dimming logic. Both devices also include precision reference capable of supplying current to low power microcontroller. Protection features include cycle-by-cycle current protection, overvoltage protection, and thermal shutdown. The TPS92641 device includes a shunt FET dimming input and MOSFET driver for high resolution PWM dimming. The TPS92640 and TPS92641 devices are high-voltage, synchronous NFET controllers for buck-current regulators. Output current regulation is based on valley current-mode operation using a controlled on-time architecture. This control method eases the design of loop compensation while maintaining nearly constant switching frequency. The TPS92640 and TPS92641 devices include a high-voltage start-up regulator that operates over a wide input range of 7 V to 85 V. The PWM controller is designed for high speed capability, including an oscillator frequency range up to 1 MHz. The deadtime between high side and low side gate driver is optimized to provide very high efficiency over a wide input operating voltage and output power range. The TPS92640 and TPS92641 devices accept both analog and PWM input signals, resulting in exceptional dimming control range. Linear response characteristics between input command and LED current is achieved with true zero LED current using low off-set error amplifier and proprietary PWM dimming logic. Both devices also include precision reference capable of supplying current to low power microcontroller. Protection features include cycle-by-cycle current protection, overvoltage protection, and thermal shutdown. The TPS92641 device includes a shunt FET dimming input and MOSFET driver for high resolution PWM dimming.