TPS7A26 Working and Its Applications

As most of our appliances work using the power supply provided by power stations, they are prone to damage when fluctuations occur. To protect such sensitive electronic devices from damages caused by voltage fluctuations, linear voltage regulator IC’s are used. One of the categories of voltage regulators is Low dropout regulator series. These are also known as LDO. LDO is capable to regulate even when the output voltage is approximate to reference voltage. Their ultra-small size, low input, and output voltage requirements make them an ideal choice for portable and battery-powered electronic devices. TPS7A26 IC is also a low dropout voltage regulator.

What is TPS7A26?

TPS7A26 is a low dropout linear voltage regulator with power-good. Available in both adjustable version and fixed voltage version, characteristics of TPS7A26 have proven it to be an ideal choice for portable devices.

This device has a very low quiescent current, which is helpful in extending battery life in portable devices. This IC uses feedback divider resistors to get more flexibility and higher output voltages in an adjustable version. TPS7A26 can provide precision regulation for microcontrollers.

Block Diagram of TPS7A26

Block diagram of TPS7A26
Block diagram of TPS7A26

Current Limit
To protect the regulator during transient high-load current faults and shorting events, an internal current limit circuit is provided. When the device is in current limit output voltage is not regulated. Because of an increase in power dissipation when current limit occurs, the device begins to heat up.

The device gets turned off if a thermal shutdown is triggered. Once the device is cooled down, the thermal shutdown circuit turns on the device. This device is provided with an independent Undervoltage lockout circuit, which monitors the input voltage.

Functional Modes
TPS7A26 operates in three modes- Normal operation, Dropout operation, and Disabled mode.

Circuit Diagram

Circuit Diagram of TPS7A26
Circuit Diagram of TPS7A26

Adjustable Device Feedback Resistors
To set the output voltage in the adjustable voltage version of TPS7A26, external feedback divider resistors are required. The output voltage is set using the feedback divider resistors R1 and R2 according to the equation

VOUT = VFB X (1 + R1/ R2)

Recommended Capacitor Types
For stability of the device, low equivalent series resistance capacitors should be used at the input and output. When using multilayer ceramic capacitors care should be taken. The effective capacitance varies with operating voltage and temperature, regardless of the ceramic capacitor type selected.

Input And Output Capacitor Requirements
If the source impedance is more than 0.5Ω input capacitor is recommended. Input capacitor helps to improve transient response, input ripple and PSRR of the device.
Use of output capacitor increases the dynamic performance of the device. A capacitor of less than 50µF is recommended.

Reverse Current
The device doesn’t have a reverse current protection circuit and can be damaged when reverse current occurs. So, a protection circuit should be applied externally if the reverse current is expected in the application.

Pin Configuration of TPS7A26

Pin Diagram of TPS7A26
Pin Diagram of TPS7A26

TPS7A26 is available as a 6 Pin WSON package. The pin configuration of this IC is as follows-

  • Pin-1 is the output pin OUT. For achieving stability, a capacitor is attached from this pin to the ground. This capacitor should be placed as close as possible to the pin.
  • Pin-2 is the feedback pin FB. This pin is used for adjustable voltage version of TPS7A26 only. It acts as input to the control-loop error amplifier. This pin along with the external resistors is used to set the output voltages of the device.
  • Pin-3 is the power-good pin PG. This pin should be externally pulled up to the OUT pin or another voltage rail. This pin goes high when the output voltage is greater than the PG threshold rising voltage of the device. PG pin goes low when the output voltage is lesser than the PG threshold falling voltage. When this pin is tied to the ground, the device has better thermal performance.
  • Pin-4 is the enable pin EN. When this pin is driven at a voltage greater than enable pin high-level input voltage of the device, the regulator will be enabled. For the voltage lower than the Enable pin low-level input voltage of the device, the regulator goes into low –current shutdown mode. If not in use, for the application, connect the pin to IN but don’t float this pin.
  • Pin-5 is the ground pin GND. Pin-6 is the input pin IN. For better transient response and to minimize the input impedance, external capacitors are used. These capacitors are connected from IN to the ground pin of TPS7A26.

Specifications

The specifications of TPS7A26 voltage regulator are as follows-

  • TPS7A26 has an input voltage in the range of 2.4V to 18V.
  • This IC is available as a fixed output voltage version and adjustable output voltage version.
  • This IC has an accuracy of 1% over temperature.
  • This voltage regulator has a low dropout voltage of 590 mV at 500mA.
  • This device has an active overshoot pull-down protection circuit.
  • This IC also has thermal shutdown and overcurrent protection circuits.
  • This IC requires capacitors for stability.
    Operating temperature range for this IC is from -400C to 1250C.
  • This IC is available as a 6-Pin WSON package.
  • This device has an ultra-low quiescent current of 2.0µA.
  • Fixed voltage version of this IC is available for the voltages of 1.25V to 5V.
  • Adjustable voltage version of this voltage regulator is available for voltages in the range of 1.25V to 1.74V.
  • For a fixed voltage version of TPS7A26 the external resistors are eliminated, so the PCB area is minimized.
  • Output capacitors of value 1 µF are enough for stability.
  • With both versions of TPS7A26 1% output regulation accuracy can be achieved.
  • TPS7A26 requires an enable voltage of 18V.
  • In this IC output current is internally limited.
  • TPS7A26 supports storage temperature of -650C to 1500C.

Applications

Applications of TPS7A26 Low dropout voltage regulator are as follows-

  • TPS7A26 is used in Home and building automation circuits.
  • Multicell power banks use this voltage regulator.
  • TPS7A26 also finds applications in smart grid and metering.
  • Portable power tools make use of features of TPS7A26 LDO.
  • Motor drives use TPS7A26.
  • White goods also use a TPS7A26 voltage regulator.
  • TPS7A26 proved to be an ideal choice for Portable Appliances.

Alternative IC

The TPS7A11 voltage regulator can be used as an alternative to TPS7A26 LDO.

With its efficiency and features like low input voltage and low output voltage requirements, TPS7A26 has proven a great choice for modern applications which need stringent energy requirements.

Its internal protection circuits help the device to operate in various temperature conditions. Further electrical characteristics can be found in the datasheet of Texas Instruments For which of your application have you used TPS7A26 IC?

Image Resource: Texas Instruments

Add Comment