The TPS65510 offers a suitable solution for power switch to select the main battery or the backup battery.

This device automatically selects the power path. It depends on the voltage level of the VO_BT pin. When the main battery is removed, the power path of the VOUT pin is automatically changed from the output of 3.3-V low droppout (LDO) voltage regulator to the backup battery.

The backup battery is charged from the power path of the VRO pin (output of 3.3-V LDO) via an external diode and resistor. The input of the LDO voltage regulator comes from the internal boost converter.

The 1.2-V output LDO and 1.8-V output LDO voltage regulators have a enable pin, V_CTRL. If these outputs are not necessary, V_CTRL should be connected to AGND to save power consumption. The self-power consumption is less than 3 µA (maximum) using the backup battery.

This device has two indicators. One is CS, which monitors the voltage level of the VBAT pin and VO_BT pin. The other is XRESET, which monitors voltage level of the VOUT pin. These indicators should be connected to CPU/DSP to reset them.

This device reduces the total solution area and extends the lifetime of the backup battery.

• Power-Path Switch to Select Main Battery or Backup Battery for Real-Time Clock (RTC)
• Integrated Boost DC/DC Converter
  • Modulation Select by Control Pin (PWMON), Pulse Frequency Modulation (PFM) or Pulse Width Modulation (PWM)
  • Fixed Switching Frequency (PWM, 750 kHz)
  • Peak Current Mode Control (PWM)
  • Low Power Consumption (PFM)
• Four Integrated Low Dropout (LDO) Voltage Regulators for 1.2 V/1.8 V/3.3 V
• Two Integrated Indicators
  • CS: Monitors the Voltage Level of Main Battery (VBAT) and Output voltage level of Boost Converter (VO_BT)
  • XRESET: Monitors the Output voltage Level of 3.3V LDO (VOUT)
• 16-Pin QFN (3mm × 3mm) Package
• Operating Temperature –35°C to 85°C
• Protection
  • Overcurrent Protection (OCP)
  • Overvoltage Protection (OVP)
  • Thermal Shutdown (TSD)
  • Undervoltage Lockout (UVLO)
• APPLICATIONS
  • Digital Still Cameras
  • Portable Systems With Backup Battery

PowerPAD Is a trademark of Texas Instruments.