switches Using a momentary push button as a latching on-off toggle switch


Posted on Feb 5, 2014

An explanation of how the thing should work. The TPS_EN line is low at first. Since it is pulled down by a 10k pull down resistor(not shown in the schematic). When the user presses S2, the mosfet Q2 turns on because ground is applied to its gate. which enables the power regulator connected to the TPS_EN line. The regulator now starts up and


switches Using a momentary push button as a latching on-off toggle switch
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starts powering the microcontroller. The microcontroller pulls the LATCH_OP1 and LATCH_OP2 low. The mosfet Q2 and Q6 now `turns on` due to this. Q6 is turned on and now causes the 1st and 2nd terminals of the push button s2 to go high. And the LATCH_OP1 causes the Q2 to latch thus enabling a constant high signal (VBATT)on the enable line. Now when the user presses the button Since Q6 was `on` the VBATT gets applied to gate of Q2 and turns off Q2. The regulator turns off. turning off the microcontroller and the LATCH_OP2 and LATCH_OP1 return to VBATT. The circuit does not work as intended. I tried manually changing the latch lines to ground when turning on and it worked. But when i connect the lines to the microcontroller it does not work Please help me out!




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