TPL5010 hardware watchdog circuit

TPL5010 real image

TPL5010 product image

When making some products with very low acquisition frequency, battery power will be considered, such as meters, electrical meters, etc. In order to control power consumption, the device will often enter a low-power mode when it does not need to work.

In order to ensure the stability of the device and prevent it from being unable to recover after a crash, a watchdog must be configured. For a general watchdog chip, the interval between dog feeding is a few seconds.

This creates a contradiction between feeding the dog and low power consumption. Frequent feeding of the dog requires frequent waking up, so it is difficult to achieve low power consumption.

This watchdog chip has an adjustable dog feeding interval from 0.1 seconds to 2 hours. When the voltage is 2.5V, the current consumption is 35nA (typical value), which is particularly suitable for the above applications.

The 2-hour interval means that the main control chip only needs to wake up and feed the dog once every 2 hours. When powered by 2.5V, the power consumption is only 35nA, which is almost negligible.

TPL5010 Application Schematic

Pin description

1. Power supply

2. GND

3. Different watchdog intervals can be achieved by adjusting the resistance of the pull-down resistor.

4. Input, pin for feeding the dog

5. Output, can wake up the main control device regularly

6. Reset pin, if the dog is not fed, reset the main control through this pin

TPL5010 Configuration

TPL5010 Pin Functions

Characteristic

● Supply voltage range is 1.8V to 5.5V

● When the voltage is 2.5V, the current consumption is 35nA (typ.)

● Optional timing interval: 100ms to 7200s

● Timer accuracy: 1% (typical value)

● Time interval selectable via resistor

●Watchdog function

● Manual reset

Application

●Battery powered system

● Internet of Things (IoT)

● Access detection

● Tamper detection

● Home automation sensors

●Temperature regulating device

● Consumer electronics

● Remote sensor

● White goods

Illustrate

● The TPL5010 nanowatt timer is an ultra-low power timer with a watchdog function designed for system wake-up functions in duty cycle, battery-powered applications such as those in the Internet of Things. Many of these applications require the use of a μC, so it is often desirable to maintain the μC in a low-power mode to maximize current savings and only wake up at certain intervals to collect data or service interrupts. Although the μC's internal timer can be used for system wake-up, it alone may consume several microamps of total system current.

● The TPL5010 consumes only 35nA and can replace the function of the integrated μC timer. This puts the μC into a much lower power mode, turns off the internal timer, and only returns to active mode when interrupted by the TPL5010.

● TPL5010 can significantly reduce battery size used in energy harvesting or wireless sensor applications by providing nearly two orders of magnitude power savings.

● TPL5010 provides selectable time intervals from 100ms to 7200s, suitable for interrupt-driven applications. For safety reasons, some standards (such as EN50271) require a watchdog function.

● TPL5010 not only implements the watchdog function, but also hardly increases power consumption.

The TPL5010 is available in a 6-pin small outline transistor (SOT23) package.