Datasheet

TPS65950
SWCS032E–OCTOBER 2008–REVISED JANUARY 2011 www.ti.com
Table 8-2. Precharge Electrical Characteristics
R
S
= 0.22 Ω, unless otherwise specified (continued)
Parameter Test Conditions Min Typ Max Unit
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 kΩ
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 μA
current
Precharge main battery Measured through ADCIN1 rising voltage and sourced 115 140 192 kΩ
presence impedance detection current, monitoring BATSTS value
threshold
Precharge main battery Force ADCIN1 voltage, monitor BATSTS value. 750 mV
presence voltage detection
threshold
Precharge main battery Measured on ADCIN1 pin 5.5 μA
presence detection output
current
8.3.3 Constant Voltage Mode
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-μF typical
external capacitor must be connected to the VBAT node.
Table 8-3 lists the electrical characteristics of CV mode.
122 Battery Interface Copyright © 2008–2011, Texas Instruments Incorporated
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