Download

PDF Abstract Text:

DV2002L2 / TL2

Control of LM317 Linear Regulator Features

DV2002L2 / TL2
Fast Charge Development System
Control of LM317 Linear Regulator Features
General Description
The DV2002L2 / TL2 Development System provides a development environment for the bq2002 and bq2002T Fast-Charge ICs. The DV2002L2 / TL2 incorporates a bq2002 / T and a linear regulator to provide fast charge control for 4 to 10 NiCd or NiMH cells. The fast charge is terminated by any of the following: T / t, maximum temperature, maximum time, or an inhibit command for the bq2002T or -V / peak voltage, maximum temperature, maximum time, and inhibit command for the bq2002. Jumper settings select the top-off and maximum time limits. The user provides a power supply and batteries. The user configures the DV2002L2 / TL2 for the number of cells and maximum charge time (with or without topoff). Please review the bq2002T or bq2002 data sheet before using the DV2002L2 / TL2 board.
Connection Descriptions
JP4 THERM BAT- BAT+ GND DC JP3 NOC JP2 INH JP1 Thermistor connection Battery ground Positive battery terminal Ground from charger supply DC input from charger supply Select number of cells Inhibit input Timer, etc. Setting
Rev. C Board
DV2002L2 / TL2 Fixed Configuration
The DV2002L2 / TL2 board has the following fixed characteristics: VCC (4.75-5.25V) is regulated on-board from the supply at connector JP4 (DC:GND). LED indicates charge status. Charge initiates on the later application of the battery or DC, which provides VCC to the bq2002 / T.
Jumper-Selectable Configuration
The DV2002L2 / TL2 must be configured as described below. INH (JP2): Enables / disables charge inhibit (see bq2002 / T data sheet). Jumper Setting 123 123 Pin State Disabled (high) Enabled (low)
Table 1. Lookup Table for R7 Selection
Input Voltage to 25V
(JP1): Selects fast charge safety time / top-off (see bq2002 / T data sheet). Jumper Setting 123 123 123 Pin State High Low Float
Current 1A 1.5A
Resistance 1.25 0.83
Wattage 2W 2W
Number of Cells (JP3): A resistor-divider network is provided to select 4 to 10 cells (the resulting resistor value equals N - 1 cells). RB1 is a 100K resistor, and RB2 (RB20-RB25) is jumper-selected. Closed Jumper R13 R12 R11 R10 R9 Number of Cells 10 8 6 5 4
Rev. C Board
Temperature Disable: Connecting a 10K resistor between THERM and BAT- disables temperature control.
Setup Procedure
1. 2. 3. Configure TM, INH, and number-of-cells (NOC) jumpers. Connect the provided thermistor or a 10K resistor between THERM and BAT-. Attach the battery pack to BAT+ and BAT-. For temperature control, the thermistor must contact the cells. Attach DC current source to DC (+) and GND (-) connections in JP4.
DV2002L2 / TL2 Recommended DC Operating Conditions
Symbol IDC VDC VBAT VTH Description Maximum input current Maximum input voltage BAT input voltage THERM input voltage Minimum 4.0 + VBAT or 10 0.5 Typical Maximum 1.5 18 + VBAT or 25 24 5 Unit A V V V
DV2002L2 / TL2 Board Schematic
1 2 3 LED BAT 4 VSS VIN VOUT ADJ
SEMITEC
D3 1N5400 JP3 BAT
R3 100K
R16 100K
Q2 2N3904
BQ2002T R4 100K
C2 0.1UF
DV2002TL2, REV C, 5 / 2 / 97
Rev. C Board