Texas Instruments TPS40190EVM-001, Руководство пользователя

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3.1 Adjusting Output Voltage (R1)
The regulated output voltage can be adjusted within a limited range by changing the ground resistor in the
feedback resistor divider (R1). The output voltage is given by
Equation 1 .
V
OUT
= V
VREF
×
R5 + R1
R1
(1)
where
• V
VREF
= 0.591 V
• R5 = 10 kΩ
Table 3-1 contains common values for R1 to generate popular output voltages. The TPS40190EVM-001 is stable
through these output voltages but the efficiency can suffer as the power stage is optimized for the 1.5-V output.
Table 3-1. Adjusting V
OUT
with R1
V
OUT
R1
3.3 V
(1)
2.15 k
2.5 V
(1)
3.09 k
2.25 V 3.57 k
2.0 V 4.22 k
1.8 V 4.87 k
1.5 V 6.49 k
1.2 V 9.76 k
(1) For output voltages greater than 2.5 V, change C11 to 330 μF, 4 V or higher PosCAP.
3.2 Adjusting Short Circuit Protection (R6)
The TPS40190 uses a selectable current limit for short circuit protection. The current limit is selected from three
levels by placing a resistor at R6. The TPS40190 compares the voltage drop across the high-side FET (VDD to
SW) to an internal reference voltage selected during start-up. The voltage levels are shown in
Table 3-2 .
Table 3-2. Adjusting V
SCP
with R6
V
SCP
R6
160 mV 3.9 k
320 mV OPEN
420 mV 12 k
The current before declaring short circuit protection can be determined by dividing the VSCP by the RDS(ON) of
the high-side FET (Q2).
3.3 Disable (TP1 and SW1)
The TPS40190EVM-001 provides both a Disable input (TP1) and a Disable switch (SW1) to allow the user to
evaluate the Enable Function of the TPS40190. When the switch is ON or TP1 is pulled high, Q1 pulls EN (U1
pin 1) to ground and disables the TPS40190 IC.
Schematic www.ti.com
4 TPS40190 Buck Controller Evaluation Module User's Guide SLUU232A – SEPTEMBER 2005 – REVISED JANUARY 2022
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