Bq20Z65 Circuit Module Schematic; Circuit Module Physical Layouts And Bill Of Materials; Components And Flash-Memory Settings For Different Precharge Modes - Texas Instruments bq20z65EVM-001 User Manual

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bq20z65 Circuit Module Schematic

This section contains information for modifying and choosing a precharge mode for bq20z65/bq29412
implementation.
3.1 Schematic
The schematic follows the bill of materials in this user's guide.
3.2 Modifications for Choosing Particular Precharge Mode
In order to charge, the charge FET (CHG-FET) must be turned on to create a current path. When the
V is 0 V and CHG-FET = ON, the V
(BAT)
voltage for the device is too low to operate. This function has three possible configurations, and the IC can
be easily configured according to the application needs. The three modes are 0-V Charge FET mode,
Common FET mode, and Precharge FET mode.
1. 0-V Charge FET mode - Dedicates a precharge current path using an additional FET (ZVCHG-FET) to
sustain the PACK+ voltage level.
2. Common FET mode - Does not use a dedicated precharge FET. The charge FET (CHG-FET) is set to
ON state as default.
3. Precharge FET mode - Dedicates a precharge current path using an additional open-drain (OD) pin
drive FET (PCHG-FET) to sustain the PACK+ voltage level.
To use a particular mode of charging with the EVM, add or remove some elements shown in
use the given settings of DF.Configuration, ZVCHG1, 0.
Table 2. Components and Flash-Memory Settings for Different Precharge
MODE
1. 0-V Chg (default)
2. Common FET
3. Precharge
For more details about precharge operation and mode choices, see the bq20z65 data sheet (SLUS878).
3.3 Testing Fuse-Blowing Circuit
To prevent the loss of board functionality during the fuse-blowing test, the actual chemical fuse is not
provided in the circuit. FET Q1 drives TP3 low if a fuse-blow condition occurs; so, monitoring TP3 can be
used to test this condition. Fuse placement on the application board is shown in the bq20z65 data sheet
reference-board schematic.
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Circuit Module Physical Layouts and Bill of Materials

This section contains the printed-circuit board (PCB) layout, bill of materials, and assembly drawings for
the bq20z65/bq29412 circuit module.
SLUU353 – June 2009
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is as low as the battery voltage. In this case, the supply
(PACK)
Modes
RESISTORS PRECHG FET
R21, R28 Q3
R24 Q2
R23, R28 Q3
bq20z65EVM-001 SBS 1.1 Impedance Track™ Technology
Enabled Battery Management Solution Evaluation Module
bq20z65 Circuit Module Schematic
Table
ZVCHG1 ZVCHG0
0 0
0 1
1 0
2, and
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