TPS65023_15 Datasheet, PDF (42/47 Pages) Texas Instruments – Power Management IC

TPS65023, TPS65023B
SLVS670K – JUNE 2006 – REVISED DECEMBER 2015
Using an external resistor divider at DEFDCDCx:
V_(bat)
10 R
1 mF
V_CC
VINDCDC3
C_I
DCDC3_EN
VDCDC3
L3
L
C_O
DEFDCDC3
AGND PGND
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V_O
R1
R2
Figure 41. External Resistor Divider
When a resistor divider is connected to DEFDCDCx, the output voltage can be set from 0.6 V up to the input
voltage V_(bat). The total resistance (R1 + R2) of the voltage divider must be kept in the 1-MR range to maintain a
high efficiency at light load.
V_(DEFDCDCx) = 0.6 V
V_OUT = V_DEFDCDCx x ^{R1 + R2}
R2
( ) ^{R1 = R2 x}
V_OUT
V_DEFDCDCx
- R2
(12)
9.2.2.5 VRTC Output
It is required that a 4.7-μF (minimum) capacitor be added to the VRTC pin even if the output is not used.
9.2.2.6 LDO1 and LDO2
The LDOs in the TPS65023x are general-purpose LDOs which are stable using ceramics capacitors. The
minimum output capacitor required is 2.2 μF. The LDOs output voltage can be changed to different voltages
between 1 V and 3.3 V using the I²C interface. Therefore, they can also be used as general-purpose LDOs in
applications powering processors different from DaVinci. The supply voltage for the LDOs needs to be connected
to the VINLDO pin, giving the flexibility to connect the lowest voltage available in the system and provides the
highest efficiency.
9.2.2.7 TRESPWRON
This is the input to a capacitor that defines the reset delay time after the voltage at VRTC rises above 2.52 V.
The timing is generated by charging and discharging the capacitor with a current of 2 μA between a threshold of
0.25 V and 1 V for 128 cycles. A 1-nF capacitor gives a delay time of 100 ms.
While there is no real upper and lower limit for the capacitor connected to TRESPWRON, TI recommends not
leaving signal pins open.
t_(reset) = 2 x 128 x
( ) (1 V - 0.25 V) x C(reset)
2 mA
where
• t_(reset) is the reset delay time
• C_(reset) is the capacitor connected to the TRESPWRON pin
(13)
The minimum and maximum values for the timing parameters called ICONST (2 uA), TRESPWRON_UPTH (1
V), and TRESPWRON_LOWTH (0.25 V) can be found under Electrical Characteristics.
42
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