TPS73701DRVT

TPS73701DRVT Application Field and Working Principle

TPS73701DRVT is a micro power low-dropout (MLDO) linear regulator designed for cost-sensitive, space-constrained applications. It is a positive voltage regulator designed to consume a minimum of external components while providing accurate output currents of up to 85mA. The TPS73701DRVT contains an internal 1A current-limit circuit and a thermal shutdown circuit. In order to optimize the performance and minimize external component count, the TPS73701DRVT regulator is designed to use small-value feedback resistors.

The TPS73701DRVT is designed to operate over a wide input voltage range of 2.5 V to 18 V and can sustain a continuous output current of up to 85mA, and can deliver up to 200mA in an unloaded per cycle, or burst mode. The regulator\'s output voltage is set using two external resistors; these resistors can be used to set the output voltage from 1.2 V to 5.5 V.

Applications

The TPS73701DRVT is designed to provide a cost effective solution for a variety of applications including: portable applications, battery powered systems, cellular phones, LCD monitors, ASSPs, MP3 players, digital still cameras, and video cameras.

Internal Architecture and Working Principle

The TPS73701DRVT comes in a small SOT-23-5 package and is constructed with minimal external components. The internal architecture consists of a PMOS SCR, an inverting amplifier, a compensated high-gain op-amp error amplifier, a current limiting circuit and a thermal shutdown circuit. The micropower LDO can be considered to be a series voltage regulator which incorporates an open-loop error amplifier, a shunt regulator and a series-pass element in a feedback loop circuit. The error amplifier compares the voltage at the output (Vout) to an internally generated reference voltage. The output of the error amplifier is given to the input of the series pass element, and based on the output of the error amplifier the series pass element varies in a manner so as to make the output voltage of the regulator equal to the reference voltage. The series-pass element supplies current to the load, while the shunt regulator operates as a low-resistance path allowing a small amount of current to “bypass” the series pass element, which helps maintain the set output value. Any decrease in the output voltage causes an increase in the current flowing through the series pass element, which causes an increase in the energy dissipated by the series pass element, which in turn causes the output voltage to increase to its target level. The current limiting circuit monitors the current flowing through the series pass element. If the pass element experiences an overload condition, the current limiting circuit will cause the series pass element to reduce the current to a safe level.

To enable the device to start with minimum input and output capacitors, the TPS73701DRVT incorporates an enable pin. This pin will enable the device when a low voltage is applied to it. The pin can also be used to pull the output voltage low (shutdown) when required. The device can be used with any type of capacitor; however, the minimum recommended output capacitance is 470µF.

Conclusion

The TPS73701DRVT is an ideal voltage regulator for applications requiring low power consumption and size restrictions. With its small SOT-23-5 package, accurate output voltage and an internal 1A current-limit circuit, the TPS73701DRVT is a great solution for cost-sensitive, space-constrained applications.