Hp50g 's board voltage

[ramon_ea1gth]

The HP 50g has four batteries, i.e., 6 V and can be USB powered (5 V). The HP 49G+ has three batteries, i.e., 4.5 V and I guess the underlying technology is the same. So, without having on hand any schematic diagram, there are chances that the internal electronics works at 3.3 V and an efficient voltage regulator is used to convert these input voltages (6 V, 5 V or 4.5 V) to the 3.3 V operating voltage of the ARM microcontroller and rest of the electronics.

Currently there are in the market amazingly efficient buck-boost voltage regulators for this task.