Flexible Sequencing

TI´s TPS40100 controller simplifies design by seamlessly supporting three common sequencing schemes found in today´s high performing power systems, including sequential sequencing, ratio-metric sequencing and simultaneous sequencing. Such flexibility allows designers to effectively address the various sequencing requirements of complex systems with multiple output voltages without having to specify different controllers for each application. This saves valuable time, design effort and cost, especially if power supply sequencing requirements change when a digital signal processor (DSP) or field programmable gate array (FPGA) is changed mid-way through the design process - saving a designer from potentially having to re-design 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.

Margining Control

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. 

Increased Efficiency and Power Supply Protection

The TPS40100 efficiently 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 today's power supplies, including pre-bias startup capability, programmable under-voltage lock out (UVLO), lossless DCR current sensing, power good indicator, synchronization input, programmable over-current protection and thermal shutdown.

Key Technical Features of TPS40100:

• 4.5-V to 18-V input range 
• Adjustable frequency (100 KHz to 600 KHz) 
• Sequential, ratio-metric and simultaneous startup sequencing 
• Output margining control ( five percent; three percent) 
• Separate SGND and PGND for remote sense 
• Start-up into pre-biased outputs 
• Accurate 0.7-V < one percent Vref 
• Peak current mode control
  

Availability, Packaging and Pricing

The TPS40100 controller is available in volume from TI and its authorized distributors. Packaged in a 24-pin QFN, suggested resale pricing is $1.45 each in quantities of 1,000 units. TI´s easy-to-use TPS40K Designer Software for the TPS40100 will be available in the third quarter of 2005.