LOW POWER

OSCILLATOR

CONTROL

FREQUENCY

DIVIDER

D0

D1

D2

RSTn

WAKE

TCAL

DONE

PGOOD

GND

VDD

TPL5000

SNAS628B – JULY 2013 – REVISED DECEMBER 2014

www.ti.com

8 Detailed Description

8.1 Overview

The TPL5000 is a long-term timer with a watchdog feature for low-power applications. The TPL5000 is designed

for use in interrupt-driven applications and provides selectable timing from 1 s to 64 s. An additional supervisor

feature is achieved through interfacing the TPL5000 to a power-management IC.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Supervisor Feature

A critical event that can corrupt the memory of a microcontroller is a voltage supply drop (supply lower than

minimum operating range), and a reset of the microcontroller is mandatory if this occurs. Since the TPL5000 is

the right choice in systems which stay most of the time in deep sleep, due to its ultra-low power consumption, it

is fundamental that it takes into account the voltage drop events.

The TPL5000 implements a supervisory functionality when working with some power-management ICs which

indicate the status of the supply voltage with a power-good or battery-good output. The supervisory functionality

is enabled by simply connecting the Battery management power-good output to the TPL5000 PGOOD pin. If this

feature is not used connect the PGOOD pin to VDD.

In case the power management IC detects a voltage drop, lowering the PGOOD line, while the microcontroller is

in deep sleep mode (in which internal supervisors are usually off), the TPL5000 internally latches that event, and

when the PGOOD returns to high, it sends out a RESET signal to the microcontroller at the end of the elapsed

delay period.

Figure 6 shows the supervisor feature of the TPL5000. The sequence F, G is a standard sequence where the

microcontroller is in deep sleep and a voltage supply drop occurs (which is highlighted by the PGOOD high to

low transition). When PGOOD is high again, a reset pulse at the end of the delay period is sent to the

microcontroller (arrow F), then the microcontroller executes its routine (memory has been reloaded upon reset)

and sends the "DONE" signal.

8

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