Data Sheet

ManualsBrandsSeeedStudio ManualsMisc. AccessoriesBAT Detector LiPo Battery Monitor v1.0

Rev 0 8

CHRG

HYS2 HYS1 the comparator drops

threshold (typical value)

the comparator rising

threshold (typical value)

0 0 1.22V 1.22×(1＋1%)

0 1 1.22V 1.22×(1＋3%)

1 0 1.22V 1.22×(1＋6%)

1 1

1.22V 1.22×(1＋10%)

0 0 1.256V 1.256×(1＋1%)

0 1 1.256V 1.256×(1＋3%)

1 0 1.256V 1.256×(1＋6%)

1 1 1.256V 1.256×(1＋10%)

Resistor divider network design

In the circuit shown in Figure 1, resistors R1, R2, R3, R4 and R5 resistor divider network, the power supply

voltage is monitored by the partial pressure after the on-chip reference voltage to compare. In the design of

the resistor divider network of resistor values, you first need to determine the user can allow the R1, R2, R3,

R4 and R5 current consumption, according to this current can determine the R1 + R2 + R3 + R4 + R5's

value, then the customer needs the voltage monitored points to determine the value of each resistor.

Suppose you want to monitor a voltage, when the voltage drops, four in ascending order of the voltage

detection points were Vth1, Vth2, Vth3 and Vth4, which Vth4 highest voltage value, Vth1 lowest voltage

value, the design steps are as follows.

(1) to determine the R1 + R2 + R3 + R4 + R5 value

Mainly based on the monitored voltage is allowed to determine the current consumed by R1 + R2 + R3 +

R4 + R5's value, the smaller the value, the greater the current consumption was monitored voltage , the

more result of partial pressure from electromagnetic interference.

(2) Calculate the value of resistor R5

R5＝(vref／Vth4)×(R1＋R2＋R3＋R4＋R5)

(3) Calculate the value of resistor R4

R4＝(vref／Vth3)×(R1＋R2＋R3＋R4＋R5)－R5

(4) Calculate the value of resistor R3

R3＝(vref／Vth2)×(R1＋R2＋R3＋R4＋R5)－R5－R4

(5) Calculate the value of resistor R2

R2＝(vref／Vth1)×(R1＋R2＋R3＋R4＋R5)－R5－R4－R3

(6) Calculate the value of resistor R1

＝(R1＋R2＋R3＋R4＋R5)－R5－R4－R3－R2

The above formula, vref values following table.