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EVM Setup and Operation
4.4 Sense and Reset Time Delay Programming (Program t
The TPS3899 device has two time delay programming pins. Placing a capacitor on CTS and CTR changes the
sense delay and reset delay respectively. Leaving CTS and CTR pins floating (no capacitor connected) will
cause the TPS3899 to use the default delay times of 50µs [max] for sense delay and 80µs [max] for reset delay.
Table 4-2. Sense and Reset Delay Programming with CTS and CTR Pins
Capacitors NC
CTS = 0.1 µF, CTR = 0.1µF
(EVM Default)
CTS = 1 µF, CTR = 1 uF
CTS = 10 µF, CTR = 10 µF
The sense and reset time delay can be programmed to any value within the range by connecting a capacitor no
larger than 10µF between the corresponding CTS or CTR pin and GND. The relationship between the external
capacitors and sense and reset time delays is given by
recommended maximum delay capacitor for the TPS3899 is limited to 10µF as this ensures there is enough time
for the capacitor to fully discharge when the reset condition occurs.
t
= 618937 x C
D-SENSE
t
= 618937 x C
D
CTR
See User-Programmable Sense and Reset Time Delay section of the TPS3899 Data Sheet for more information.
Figure 4-1
and
Figure 4-2
captures were taken with a shunt on J3, J4, and J5 (Rdiv [pin 3] to GND [pin 2]).
Figure 4-1. Sense Delay Oscilloscope Capture
10
TPS3899EVM Voltage Supervisor User Guide
(Sense Delay, Programmed with CTS)
+ t
(no cap) (1)
CTS
D-SENSE
+ t
(no cap) (2)
D
show oscilloscope captures of sense delay and reset delay on the EVM. These
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and t
D-SENSE
t
D-SENSE
50µs [max]
61.94ms
619ms
6.19s
Equation 1
and
Equation 2
Figure 4-2. Reset Delay Oscilloscope Capture
)
D
t
D
(Reset Delay, Programmed with CTR)
80µs [max]
61.97ms
619ms
6.19s
respectively. The
SLVUBZ3 – SEPTEMBER 2020
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(1)
(2)
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