BIO-SIGNAL MEASURING DEVICE
FIG4 is circuit diagrams showing two specific examples of a non-linear circuit in the second example  FIG3 is a schematic diagram showing a second example of the bio-signal and feed power distribution means
As the non-linear circuit 321, a non-linear circuit 322 having a bridge connection of four diodes D1 to D4 shown in FIG4(a) and a capacitor C, and a non-linear circuit 323 having a bridge connection of transistors (in this example, FETs) Tr1 to Tr4 as four semiconductor switches shown in FIG4(b) and a capacitor C can be exemplified. In a case where a diode D is used as shown in FIG4(a), since the rising voltage of the diode D is in a range of 0.5 to 0.7 V, the diode D is not turned on in a normal bio-signal. Therefore, there is no case where the bio-signal flows into the charging circuit 200. Further, in a case where a transistor (FET) Tr is used as shown in FIG4(b), the transistor Tr can further increase an on-voltage according to a threshold value or reduce a leak current. The non-linear circuits 322 and 323 shown in FIG4(a) and 4(b) may be used for the rectifying circuit 325.  As a second example of the bio-signal and feed power distribution means 300, in the case of DC power feed, as shown in FIG3, a DC cut filter 311 is used for the signal transfer circuit 310. The DC cut filter 311 allows passage of the bio-signal (alternating current) and blocks the passage of DC power. The DC cut filter 311 may be a capacitor. Further, in the case of the DC power feed, as shown in FIG3, a non-linear circuit 321 is preferably adopted for the power transfer circuit 320. The non-linear circuit 321 has low impedance when power feed voltage is high voltage, and has high impedance at low voltage such as biological voltage, and functions as the power transfer circuit 320.
diagrams, schematic diagram
310
signal transfer circuit
210
battery
321
non-linear circuit
100
bio-signal processing circuit
323
non-linear circuits non-linear circuit
311
DC cut filter
320
power transfer circuit
200
charging circuit
322
non-linear circuits non-linear circuit
['1. A bio-signal measuring device comprising: a bio-signal measuring instrument which is used in a state of being mounted to a living body, wherein the bio-signal measuring instrument includes a battery as an internal power source and a charging circuit for the battery, a plurality of electrodes which are brought into contact with a skin surface of a human body at the time of bio-signal measurement and are connected to a predetermined power feeder at the time of charging of the battery, a bio-signal processing circuit which processes bio-signals detected at the electrodes in a predetermined manner, and bio-signal and feed power distribution means, the bio-signal processing circuit and the charging circuit are switchably connected to the electrodes through the bio-signal and feed power distribution means, at the time of the bio-signal measurement, the bio-signals detected at the electrodes are supplied to the bio-signal processing circuit through the bio-signal and feed power distribution means, and at the time of the charging of the battery, feed power which is supplied from the power feeder is supplied to the charging circuit through the bio-signal and feed power  distribution means.', '3. The bio-signal measuring device according to claim 2, wherein in a case where the feed power which is supplied from the power feeder is a direct current, a DC cut filter is used for the signal transfer circuit and a non-linear circuit which includes a diode or a transistor is used for the power transfer circuit.']