Digital portable pulse oximeter and battery-powered control method thereof

A digital portable pulse oximeter power supply control method comprising a housing body, said housing body consisting of an upper housing body and a lower housing body, which are disposed such that they are stacked together, one end of both the upper housing body and the lower housing body being a measurement end where a finger is placed, a pivot and a reset spring being disposed between the upper housing body and the lower housing body enabling them to be opened and closed at the measurement end, a power supply battery and a measurement analysis circuit being disposed in the housing body, the measurement analysis circuit comprising a microprocessor having a power supply stay-on output pin;

• a Hall switch sensor, a magnet and a switch circuit also being disposed in the housing body, the Hall switch sensor and the magnet being respectively disposed in the upper housing body and the lower housing body at the measurement end of the housing body, the magnet inducing the output pin of the Hall switch sensor to generate a high-low potential change through the opening and closing of the upper housing body and the lower housing body, wherein the switch circuit includes a dual-input logic NAND gate circuit and a power switch device, the output pin of the Hall switch sensor connects to one input end of the dual-input logic control gate circuit, the power supply stay-on output pin of the microprocessor connects to the other input end of the dual-input logic control gate circuit, the output end of the dual-input logic control gate circuit connects to the control pin of the power switch device, the input of the power switch device connects to the power supply battery, and the output of the power switch device connects to the measurement analysis circuit of the oximeter, the said power supply control method is:
• a. the battery powers the measurement analysis circuit and the display of the oximeter, i.e., the upper housing body and the lower housing body of the oximeter at the measuring end are opened, the output pin of the Hall switch sensor generates a high potential, which causes the output of the dual-input logic control gate circuit to control the power switch device into conduction;
• b. within a certain time, the microprocessor determines whether a blood oxygen signal is measured, i.e., whether a finger has ever been placed in the oximeter within a certain time;
• b1. if there is a blood oxygen signal measured, the power supply will stay on, i.e., the power supply stay-on output pin of the microprocessor outputs a power supply stay-on signal;
• b2. if there is no blood oxygen signal measured, a signal requiring to cut off the power supply will be sent out, i.e., the power supply stay-on output pin of the microprocessor outputs a signal of cutting off the power supply stay-on;
• c. the microprocessor determines whether the upper housing body and the lower housing body at the measurement end of the oximeter housing body are still open, that is, whether the output pin of the Hall chip is still generating a high potential;
• c1. if the output pin of the Hall switch sensor generates a high potential, the power supply will stay on;
• c2. if the output pin of the Hall switch sensor generates a low potential, the output of the dual-input logic control gate circuit will control the power switch device into non-conduction, and the power supply will be cut off.