TPS3710-Q1 Datasheet, PDF (13/22 Pages) Texas Instruments – Wide VIN Voltage Detector

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TPS3710-Q1
SBVS341 – JULY 2017
8.2 Typical Application
The TPS3710-Q1 device is a wide-supply voltage comparator that operates over a V_DD range of 1.8 to 18 V. The
monitored voltage is set with the use of external resistors, so the device can be used either as a precision
voltage monitor.
VMON
R1
2.21 MŸ
R2
83.5 kŸ
0.01 F
1.8 V to 18 V
VPULLUP
Up to 18 V
VDD
SENSE
OUT
RP
49.9 kŸ
To a reset or enable
input of the system.
GND
Figure 17. Wide VIN Voltage Monitor
8.2.1 Design Requirements
For this design example, use the values summarized in Table 2 as the input parameters.
PARAMETER
Monitored voltage
Table 2. Design Parameters
DESIGN REQUIREMENT
12-V nominal rail with maximum falling
threshold of 10%
DESIGN RESULT
V_MON(UV)= 10.99 V (8.33%)
8.2.2 Detailed Design Procedure
8.2.2.1 Resistor Divider Selection
The resistor divider values and target threshold voltage can be calculated by using Equation 1 to determine
V_MON(UV).
V_MON(UV)
=
§
¨©^{1 +}
R1 ·
R2 ^¸¹
× V_IT
(1)
where
• R1 and R2 are the resistor values for the resistor divider on the SENSEx pins
• V_MON(UV) is the target voltage at which an undervoltage condition is detected
Choose R_TOTAL ( = R1 + R2) so that the current through the divider is approximately 100 times higher than the
input current at the SENSE pin. The resistors can have high values to minimize current consumption as a result
of low input bias current without adding significant error to the resistive divider. For details on sizing input
resistors, refer to application report SLVA450, Optimizing Resistor Dividers at a Comparator Input, available for
download from www.ti.com.
Copyright © 2017, Texas Instruments Incorporated
Product Folder Links: TPS3710-Q1
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