JAJSP02C march 2011 – april 2023 TLV3011-Q1 , TLV3011B-Q1 , TLV3012-Q1 , TLV3012B-Q1
PRODUCTION DATA
Configure the circuit as shown in Figure 10-3. Connect (V+) to VBAT which also powers the microcontroller. Resistors R1 and R2 create the under-voltage alert level of 2.0 V. When the battery voltage sags down to 2.0 V, the resistor divider voltage crosses VREF, the 1.242 V reference threshold of the TLV3012-Q1. This causes the comparator output to transition from a logic high to a logic low. The push-pull output of the TLV3012-Q1 is selected since the comparator operating voltage is shared with the microcontroller which is receiving the under-voltage alert signal.
Equation 2 is derived from the analysis of Figure 10-3.
where
Rearranging Equation 2 and solving for R1 yields Equation 3.
For the specific undervoltage detection of 2.0 V using the TLV3012-Q1, the following results are calculated.
where
Choose RTOTAL (R1 + R2) such that the current through the divider is at least 100 times higher than the input bias current (IBIAS). The resistors can have high values to minimize current consumption in the circuit without adding significant error to the resistive divider.