Wiring Circuit

A rectangular-wave pulse generator with an especially long period may additionally be constructed the usage of most effective two parts: a National Semiconductor LM3710 supervisor IC and a 100-nF capacitor to do away with noise spikes. This circuit utilises the watchdog and reset timers within the LM3710. The watchdog timer is reset when an facet seems on the WDI enter (pin 4). If WDI is constantly held at floor degree, there are usually not any areas and the watchdog times out. After an interval TB, it triggers a reset pulse with a length TA and is reloaded with its initial price. The cycle then begins all over once more. As a result, pulses with a period of TA + TB are existing on the RESET output (pin 10).

 Long-Interval Pulse Generator Circuit Diagram

As may additionally be viewed from the table, periods ranging as a lot as around 30 2ds may additionally be done on this manner. The two intervals TA and TB are determined by internal timers in the IC, which is available in quite quite a bit of models with 4 completely different varys for every timer. To obtain the specified interval, it's vital to order the fitting version of the LM3710. The type designation is decoded in the accompanying desk. 

The reset threshold voltage is beside the point for this explicit utility of the LM3710. The versions shown in daring face had been to be had on the time of printing. Current information can be found on the manufacturer’s house page (www.national.com). The numbers in brackets point out the minimal and maximum worths of intervals TA and TB for which the LM3710 is tested. The circuit functions with a provide voltage within the vary of 3–5 V.

Author: Gregor Kleine Copyright: Elektor Electronics