TI TPS54626PWPR

The TPS54626 is an adaptive on-time D-CAP2™ mode synchronous buck converter. It helps system designers complete power bus regulator sets for various end equipment with a cost-effective, low component count, low standby current solution. The main control loop uses D-CAP2™ mode control, which achieves extremely fast transient response without external compensation components. Adaptive on-time supports seamless operation between PWM mode under heavy load conditions and frequency reduction operation under light load for high efficiency. Proprietary circuitry also enables the device to accommodate low ESR output capacitors such as special polymer capacitors (SP-CAP) and ultra-low ESR ceramic capacitors. The device operates over a VIN input supply voltage range of 4.5V to 18V. The output voltage can be set between 0.76V and 5.5V. The device also features an adjustable soft-start time and a power-good function. It is offered in a 14-pin HTSSOP package, designed for an operating temperature range of -40° to 85°.

The TPS54626 is a 6.5-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs and auto-skip Eco-mode™ to improve light load efficiency. It operates using D-CAP2™ mode control. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and special polymer types.

The main control loop of the TPS54626 is an adaptive on-time PWM controller that supports a proprietary D-CAP2™ mode control. D-CAP2™ mode control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low ESR and ceramic output capacitors. It is stable with virtually no ripple at the output.

TPS54626 uses an adaptive on-time control scheme and does not have a dedicated on board oscillator. The TPS54626 runs with a pseudo-constant frequency of 650 kHz by using the input voltage and output voltage to set the on-time one-shot timer. The on-time is inversely proportional to the input voltage and proportional to the output voltage. Therefore, when duty ratio is VOUT/VIN, the frequency is constant.

The TPS54626 is designed with Auto-Skip mode to increase light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to point that its rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when its zero inductor current is detected. As the load current further decreases the converter run into discontinuous conduction mode. The on-time is kept almost the same as it was in the continuous conduction mode so that it takes longer time to discharge the output capacitor with smaller load current to the level of the reference voltage.

• D-CAP2™ mode for fast transient response, low output ripple, compatible with ceramic output capacitors
• Wide VIN input voltage range: 4.5V to 18V
• Output voltage range: 0.76V to 5.5V
• High-efficiency integrated FETs optimized for lower duty cycle applications — 36mΩ (high-side) and 28mΩ (low-side)
• High efficiency at shutdown, quiescent current below 10μA
• High initial bandgap reference accuracy
• Adjustable soft-start
• Pre-bias soft-start
• 650kHz switching frequency (fSW)
• Cycle-by-cycle current limiting
• Power-good output
• Automatic skip Eco-mode™ for high efficiency at light load

• Wide application in low-voltage systems
• Digital TV power supplies
• HD Blu-ray Disc players
• Network home terminal equipment
• Digital set-top boxes (STB)