
8.3.3
Constant Voltage Mode
TPS65950
Integrated Power Management/Audio Codec
www.ti.com
SWCS032 – OCTOBER 2008
Table 8-2. Precharge Electrical Characteristics
RS = 0.22 , unless otherwise specified (continued)
Parameter
Test Conditions
Min(1)
Typ(2)
Max(3)
Unit
Slow precharge loop accuracy
After TRIMinG, VAC = 5.4 V or VBUS = 5.0 V,
14
17.2
20.3
mV
VBAT = 1.5 V, VCCS–VBATS rising voltage, monitoring
ICTLAC1 or ICTLUSB1
Fast precharge loop accuracy
After TRIMinG, PCHGAC or PCHGUSB floating,
56
68.8
81.2
mV
VAC = 5.4 V, VBAT = 3.0 V, VCCS–VBATS rising voltage,
monitoring ICTLAC1 or ICTLUSB1
Precharge constant voltage
System did not start after VBAT > 3.2 V, VBATS input.
3.4
3.6
3.8
V
loop limitation
VBUSOVPRECH threshold (for
VBUS input
5.04
5.25
5.46
V
USB reliability)
Ac charger overvoltage
VBAT = 2.8 V, VAC input
6.5
6.8
7.3
V
threshold
VBUS overvoltage threshold
VBAT = 2.8 V, VBUS input
6.5
6.8
7.3
V
Battery voltage threshold to
VBATS input
1.8
2.0
2.2
V
start ac fast precharge
Battery voltage threshold to
VBATS input
1.0
1.2
1.4
V
start ac slow precharge
Charger presence detect
VBATS = 2.8 V, rising edge
VBAT+0.3
VBAT+
VBAT+0.6
V
threshold
0.4
VBATS = 2.8 V, falling edge
VBAT
VBAT+
VBAT+0.3
0.1
VBUS presence detect
Rising edge
4.4
V
threshold
Falling edge
4.3
BCIAUTO detection impedance
To obtain CVENACA = BCIAUTOACA = 0
10
k
threshold
To obtain CVENACA = BCIAUTOACA = 1
140
BCIAUTO detection voltage
CVENACA = 0 below the voltage threshold
100
150
200
mV
threshold
CVENACA = 1 below the voltage threshold
700
750
800
BCIAUTO detection output
Measured on BCIAUTO pin
4.5
7.5
9.5
A
current
Precharge main battery
Measured through ADIN1 rising voltage and sourced
115
140
192
k
presence impedance detection
current, monitoring BATSTS value
threshold
Precharge main battery
Force ADIN1 voltage, monitor BATSTS value.
750
mV
presence voltage detection
threshold
Precharge main battery
Measured on ADIN1 pin
5.5
A
presence detection output
current
The BCI supports a constant voltage (CV) mode. CV mode is automatically started when there is no
battery pack, a regulated ac charger is plugged in, and CVENAC = 1. The charging device outputs a
constant voltage at the VBAT node. To start CV mode, the precharge analog hardware detects whether a
battery pack is open using the battery presence comparator, and detects whether an ac charger is
connected using the ac charger presence comparator.
CV mode is disabled when VAC is greater than 6.5 V typical. Ac overvoltage protection is also enabled
during CV mode.
Hardware implementation for CV mode uses the main charge constant voltage loop. In CV mode, a 35-mA
typical load is synced internally to keep the regulated VBAT voltage output stable. An 80-
F typical
external capacitor must be connected to the VBAT node.
Table 8-3 lists the electrical characteristics of CV mode.
Battery Interface
123