Datasheet

TPS54062

SLVSAV1B –MAY 2011–REVISED AUGUST 2012

www.ti.com

Overvoltage Transient Protection

The TPS54062 incorporates an overvoltage transient protection (OVTP) circuit to minimize voltage overshoot

when recovering from output fault conditions or strong unload transients on power supply designs with low value

output capacitance. For example, when the power supply output is overloaded the error amplifier compares the

actual output voltage to the internal reference voltage. If the VSENSE pin voltage is lower than the internal

reference voltage for a considerable time, the output of the error amplifier will respond by clamping the error

amplifier output to a high voltage. Thus, requesting the maximum output current. Once the condition is removed,

the regulator output rises and the error amplifier output transitions to the steady state duty cycle. In some

applications, the power supply output voltage can respond faster than the error amplifier output can respond, this

actuality leads to the possibility of an output overshoot.

The OVTP feature minimizes the output overshoot, when using a low value output capacitor, by implementing a

circuit to compare the VSENSE pin voltage to OVTP threshold which is 109% of the internal voltage reference. If

the VSENSE pin voltage is greater than the OVTP threshold, the high side MOSFET is disabled preventing

current from flowing to the output and minimizing output overshoot. When the VSENSE voltage drops lower than

the OVTP threshold, the high side MOSFET is allowed to turn on at the next clock cycle.

Thermal Shutdown

The device implements an internal thermal shutdown to protect itself if the junction temperature exceeds 146°C.

The thermal shutdown forces the device to stop switching when the junction temperature exceeds the thermal

trip threshold. Once the die temperature decreases below 146°C, the device reinitiates the power up sequence

by restarting the internal slow start.

DESIGN GUIDE – STEP-BY-STEP DESIGN PROCEDURE No.1

Figure 20. Application Schematic

This example details the design of a continuous conduction mode (CCM) switching regulator design using

ceramic output capacitors. If a low output current design is needed go to the design procedure Number 2. A few

parameters must be known in order to start the design process. These parameters are typically determined at the

system level. For this example, we will start with the following known parameters:

Output Voltage 3.3V

Transient Response 0 to 50mA load step ΔV

OUT

= 4%

Maximum Output Current 50mA

Input Voltage 24 V nom. 8V to 60V

Output Voltage Ripple 0.5% of V

OUT

Start Input Voltage (rising VIN) 7.88V

Stop Input Voltage (falling VIN) 6.66V

Product Folder Link(s): TPS54062