Texas Instruments Rolls Out Power Supply For Merced

Electronic News, Oct 12, 1998

The synchronous-buck power supply controller from TI, model TPS5210, can control regulator circuits for high-performance processors above 30 Amps of output current and enable more than 90 percent efficiency.

This integrated device uses a hysteretic controller and provides claimed high levels of initial setpoint accuracy -- 1 percent over the full operating temperature range.

"The lower voltages and higher currents of today's Pentium-class processors and future 64-bit Merced processors demand a new generation of power supply controllers," noted Les Hodson, system engineering manager for TI's Power Management Products. "Our controller, designated the TPS5210, meets the need for high output current and fast transient response while consuming only 120 milliwatts of power."

When output current increases at high rates such as 30 Amps per microsecond, the TPS5210 can recover to the original output value in under 2 microseconds, TI said. However, the TPS5210 is "instantaneously in regulation" as the result of an integrated hysteretic control scheme that works as follows: the designer selects an acceptable window around the reference voltage and programs the TPS5210 using a resistor.

The device then compares the output voltage to the programmed window, turning the high-side FET on and off to maintain Vout within the window. Propagation delay from the comparator inputs to the output drives is claimed to be less than 250 nanoseconds. The user-selectable hysteretic controller and droop compensation in the TPS5210 dramatically reduce overshoot and undershoot caused by load transients.

The TPS5210 is available now from TI in a 28-pin SOIC package and a 28-pin PowerPAD package, priced at $2.25 when purchased in quantities of 10,000. The TPS5210 features include: hysteretic controller, 2 Amp synchronous-buck drivers, 30V-rated bootstrapped high-side driver, internal drive regulator, integrated Schottky bootstrap diode, active deadtime control, adjustable droop compensation, noise immunity circuitry, programmable soft-start, lossless current sensing, adjustable current limit, overvoltage protection, Vcc undervoltage lockout, inhibit comparator and power-good output.

The device has a programmable output voltage range of 1.3V to 3.5V, determined by a 5-bit integrated DAC. This level of integration reduces component count and produces a printed circuit board footprint that TI said is 50 percent smaller than a comparable discrete solution. A dc-to-dc converter solution based on the TPS5210 can be realized for less than $9, according to TI estimates. u