MAX6499 Overvoltage and Undervoltage Protection

The MAX6499 comprises undervoltage and overvoltage comparators for window detection. WHen the monitored voltage is within selected “window”, GATE is enhances and the n-channel MOSFET is on. GATE falls to OUTFB when the monitored voltage falls below the lower limit (V triplow) or exceeds the upper limit (Vtriphigh) of the window, turning off the MOSFET. The MAX6499 enabling the DC-DC […]

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MAX6495 Overvoltage Limiter

To protect downstream circuits from overvoltage conditions that show up during load-dump events or transients, we can use the MAX6495–MAX6499/MAX6397/MAX6398 overvoltage protection (OVP) devices. Here’s the circuit diagram: This devices work by controlling an n-channel MOSFET wired in series with the power rail. The gate pulls low and the MOSFET shuts off, disconnecting the power rail when the voltage surpasses […]

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Automatic Switching for Battery – USB Power Connection

This is a simple circuit for automatic switchover between battery and USB port. This circuit uses more general step-up converter architecture. Compared with an analog switch or diode-OR circuitry , this circuit is simpler. Here is the circuit : This circuit uses the MAX1795/MAX1796/MAX1797 step-up converter. To connect the output of a step-up converter and the USB power line, a […]

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