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calcpsu / cphp82001

CalcPack replacement for HP 82001, suits HP35/45/55/65/67 calculators
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Simplification - unregulated only #6

Closed grob6000 closed 1 month ago

grob6000 commented 2 months ago

The board is currently pretty dense for a 2-layer.

Considering eliminating the regulator: the regulator adds some idle current, and has limited benefit other than the small additional run time for HP35 only. The 4.3V potential maximum batttery voltage has been tested to work fine on a range of designs (35, 45, and 67). In fact, for the HP67, which has the card reader / amplifier IC permanently connect to battery (even during charging), the 5.6V zener clamp voltage has not caused any issue (the IC architecture is resistant to at least 6.5V it seems).

In my calculators, I've settled on the unregulated design being the preference.

I can split the design into two board layouts - one for regulated, one for unregulated, allowing more space for better layout (e.g. better thermal pads for easier assembly etc.).

grob6000 commented 1 month ago

Unregulated design only for v5: 30ffbc13f589585e5461ab38b471176c49de2603