The following project is built:
- A 9 V battery is used – no socket required. This is important to gain experience for future projects.
- There is an under-voltage lockout, which switches off when the battery becomes weak.
- A 555 timer, wired as an oscillator and with a 50% duty cycle, makes a red LED flash.
- The circuit is designed to save power.
- Unfortunately, the circuit is not yet power saving enough.
When I do the math: I buy this 9 V battery with 1200 mAh, and the circuit consumes 20 mA, then it runs for 60 h – so less than 3 days. I have to change that. The point is that this is the first milestone. Later, the circuit will be extended. I want to connect a microprocessor to the same battery later.
I only work with PSpice for TI 2022; this is a cut-down version of PSpice; in other words, I only have models from PSpice and Texas Instruments available.
By the way: the operational amplifier in the UVLO gets its own 9 V battery. This way the voltage is always the same, as it consumes very little current.