Texas Instruments TPS61291DRVT

Overview

TPS61291 from Texas Instruments is a low-quiescent-current boost converter with integrated bypass switch, designed for battery-powered systems requiring dual-mode operation. It delivers 200mA+ output at 3.3V from 1.8V input in boost mode and provides direct VIN-to-VOUT conduction with only 15nA quiescent current in bypass mode-enabling ultra-low-power MCU operation (e.g., MSP430) from single 3V Li-MnO₂ or dual alkaline cells.

For engineers reviewing the TPS61291 datasheet, TPS61291 pinout, TPS61291 application, or TPS61291 equivalent, key selection criteria include its 0.9–5V input range, pin-selectable 2.5V/3.0V/3.3V outputs, controlled bypass transition to prevent reverse battery current, thermal shutdown, and redundant overvoltage protection-critical for metering, remote controls, and home automation designs where battery life and system voltage stability are paramount.

Technical Context

The TPS61291 implements a hysteretic current-mode control architecture with synchronous rectification, enabling fast load transient response and high efficiency across wide input/output conditions. Its dual-path topology integrates a P-channel bypass switch and a current-limited boost power stage, with independent EN/BYP control determining operational mode.

Startup uses an internal oscillator until VOUT reaches ~1.8V, then transitions to normal regulation; VSEL pin state is latched at startup to select one of three fixed output voltages via internal feedback divider networks-disconnected during bypass to achieve 15nA IQ. Overtemperature protection (140°C threshold, 20°C hysteresis) and redundant OVP (5.4V clamp) operate exclusively in boost mode.

Key Specifications

Pinout & Package

TPS61291 is housed in a thermally enhanced 2mm × 2mm × 0.75mm SON-6 package (DRV) with exposed thermal pad soldered to GND for optimal heat dissipation in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost-with-bypass applications.

Compared with TPS61292DRVT, the TPS61291 offers identical performance at lower cost and qualification grade for standard industrial use; compared with MAX17222ETA+, it provides essential bypass operation and pin-selectable outputs-but at higher boost-mode IQ.

Availability

TPS61291 is available at Aetrix Electronics and suitable for gas/water smart meters, IR remote controls, and home security sensors requiring stable component supply with long-term lifecycle support and traceable sourcing.

Supply support for TPS61291 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in power management ICs for battery-constrained applications.

The TPS61291 belongs to TI's ultra-low-power boost converter family, engineered specifically for energy-harvesting and long-life battery systems where minimizing quiescent current and enabling intelligent power-path control are primary design objectives.

FAQ

What is the minimum input voltage required to start up the TPS61291?

The TPS61291 requires a minimum input voltage of 1.5V at the VIN pin to initiate startup under a 20mA load condition. This allows reliable operation from partially discharged alkaline or lithium coin cells. Once started, the device continues regulating down to 0.9V input. The startup oscillator activates below 1.8V to build initial output voltage before transitioning to normal hysteretic control.

How does the TPS61291 prevent reverse current flow into the battery during bypass mode transition?

The TPS61291 incorporates a controlled bypass transition circuit that delays activation of the internal P-channel bypass switch until the output voltage (VOUT) has dropped to match the input voltage (VIN). This prevents stored charge in the output capacitor from flowing backward through the bypass switch into the battery-a critical feature for preserving battery chemistry and preventing leakage-induced capacity loss in long-life applications like smart meters.

Can the output voltage of the TPS61291 be changed dynamically during operation?

No-the output voltage of the TPS61291 is set only once at startup based on the logic level present on the VSEL pin (GND = 3.3V, VOUT = 3.0V, floating = 2.5V) and internally latched. Changing VSEL during operation has no effect on the regulated output voltage. To change output voltage, the device must be fully reset by toggling EN/BYP or cycling VIN.

What is the maximum continuous output current the TPS61291 can deliver in boost mode at 3.3V output?

The TPS61291 delivers a minimum of 200mA continuous output current at 3.3V VOUT when supplied from 1.8V VIN, per datasheet specifications. Under ideal thermal conditions and with appropriate external components (3.3µH inductor, 22µF COUT), peak output current capability reaches approximately 300mA before entering current-limit protection. Actual sustained current depends on input voltage, ambient temperature, and PCB thermal design.

Does the TPS61291 provide overvoltage protection in bypass mode?

No-the redundant overvoltage protection (OVP) circuit in the TPS61291 operates exclusively in boost mode and is disabled during bypass mode. In bypass, VOUT directly follows VIN, so output voltage is inherently limited by the input source. Therefore, OVP is not applicable or active when EN/BYP is low; system-level protection must be implemented externally if required.