TI Unveils TPS40100 Single-Chip Power Controller
Texas Instruments Inc. (TI, Dallas, TX) unveiled its new single-chip TPS40100 synchronous dc-dc buck controller with sequencing and output-voltage margining features, which is used in modular and on-the-board power supplies. The TPS40100 reduces the number of external circuits in 4.5 V to 18 V telecom and networking power systems with multiple output voltages, and will be incorporated into future POLA™ plug-in power modules.
The TPS40100 controller supports three common sequencing schemes found in high-performing power systems, including sequential sequencing, ratio-metric sequencing, and simultaneous sequencing, allowing designers to address the various sequencing requirements of complex systems with multiple output voltages without having to specify different controllers for each application, and saving designers from having to redesign the entire power system.
Using the device's power-good function, the TPS40100 can implement a sequential sequencing scheme, where a single power supply output voltage will ramp up and settle at its final regulation voltage before the next power supply voltage ramps up. By using a soft-start capacitor, the TPS40100 is able to implement a ratio-metric scheme that proportionally ramps up both power supply outputs at the same time until proper regulation is reached. Finally, the device can effectively implement a simultaneous sequencing scheme through its integrated amplifier.
In addition to supporting various sequencing implementations, the TPS40100 incorporates a simple margining control function that allows a power system designer to temporarily adjust the output voltage to a value either above or below the nominal regulation voltage. Two digital input pins allows the user to margin up or margin down the power supply by plus or minus five percent or plus or minus three percent. This feature enables a power supply manufacturer to verify a board's compliant operation while at the limits of the power supply's tolerance.
The TPS40100 manages power supplies up to 15 A with peak efficiencies of 90 percent. In addition, the synchronous peak current-mode controller with on-chip adaptive gate drive provides a peak current-mode control loop, which allows simple compensation insensitive to wide variations of output capacitance. For improved load regulation, separate power ground and signal ground pins provide high-accuracy remote-load sensing.
The device is also equipped with all supervisory and control features for power supplies, including pre-bias startup capability, programmable under-voltage lockout, lossless DCR current sensing, power-good indicator, synchronization input, programmable over-current protection, and thermal shutdown.
The TPS40100 controller is now available in volume. Packaged in a 24-pin QFN, pricing is $1.45 each in quantities of 1,000 units. The TPS40K Designer Software for the TPS40100 will be available in the third quarter of 2005.
