The TPS40195 is a flexible synchronous buck controller that operates from a nominal 4.5 V to 20 V supply. This controller implements voltage mode control with the switching frequency adjustable from 100 kHz to 600 kHz. Flexible features found on this device include selectable soft-start time, programmable short circuit limit, programmable undervoltage lockout (UVLO) and synchronization capability. An adaptive anti-cross conduction scheme is used to prevent shoot through current in the power FETs. Over-current detection is done by sensing the voltage drop across the low-side MOSFET when it is on, and comparing it with a user programmable threshold.

The threshold is set with a single external resistor connected from ILIM to GND. Pulse-by-pulse limiting (to prevent current runaway) is provided by sensing the voltage across the high-side MOSFET when it is on and terminating the cycle when the voltage drop rises above a fixed threshold of 550 mV. When the controller senses an output short circuit, both MOSFETs are turned off and a timeout period is observed before attempting to restart. This provides limited power dissipation in the event of a sustained fault. Synchronization on this device is bi-directional. Devices can be synchronized 180° out of phase to a chosen master TPS40195 running at a fixed 250 kHz or 500 kHz, or can be synchronized to an outside clock source anywhere in the 100 kHz to 600 kHz range.

• Input Operating Voltage Range: 4.5 V to 20 V
• Output Voltage as Low as 0.591 V ±0.5%
• 180° Bi-Directional Out-of-Phase Synchronization
• Internal 5-V Regulator
• High and Low MOSFET Sense Overcurrent
• 100 kHz to 600 kHz Switching Frequency
• Enable and Power Good
• Programmable UVLO and Hysteresis
• Thermal Shutdown at 150°C
• Selectable Soft-Start
• Pre-Bias Output Safe