ltc6803g-3 Linear Technology Corporation, ltc6803g-3 Datasheet - Page 25

• Manufacturer Part Number: ltc6803g-3
• Description: Ltc6803-1/ltc6803-3 - Multicell Battery Stack Monitor
• Manufacturer: Linear Technology Corporation

OPERATION
Table 13. Memory Bit Descriptions (continued)
NAME
MCxI
CxV
CxUV
CxOV
ETMPx
THSD
REV
ITMP
PEC
REF
*Voltage equations use the decimal value of the registers, 0 to 4095 for 12-bit and 0 to 255 for 8-bit registers
SERIAL COMMAND EXAMPLES
Examples below use a configuration of three stacked
LTC6803-1 or LTC6803-3 devices: bottom (B), middle
(M), and top (T)
Write Configuration Registers (Figure 8)
1. Pull CSBI low
2. Send WRCFG command and its PEC byte
3. Send CFGR0 byte for top device, then CFGR1 (T), …CFGR5 (T), PEC of CFGR0(T) to CFGR5(T)
4. Send CFGR0 byte for middle device, then CFGR1 (M) … CFGR5 (M) ), PEC of CFGR0(M) to CFGR5(M)
5. Send CFGR0 byte for bottom device, then CFGR1 (B), … CFGR5 (B) ), PEC of CFGR0(B) to CFGR5(B)
6. Pull CSBI high; data latched into all devices on rising edge of CSBI. S pins respond as data latched.
Calculation of serial interface time for sequence above:
Number of devices in stack = N
Number of bytes in sequence = B = 2 command byte and 7 data bytes per device = 2 + 7 • N
Serial port frequency per bit = F
Time = (1/F) • B • 8 bits/byte = (1/F) • (2 + 7 • N) • 8
Time for 3-cell example above, with 1MHz serial port = (1/1000000) • (2 + 7 • 3) • 8 = 184µs
DESCRIPTION
Mask Cell x Interrupts
Cell x Voltage*
Cell x Undervoltage Flag
Cell x Overvoltage Flag
External Temperature Measurement*
Thermal Shutdown Status
Revision Code
Internal Temperature Measurement*
Packet Error Code
Reference Voltage for Diagnostics
VALUES
x = 1..12 0 = enable interrupts for cell ‘x’ (default)
x = 1..12 12-bit ADC measurement value for cell ‘x’
x = 1..12 cell voltage compared to V
x = 1..12 cell voltage compared to V
Temperature measurement voltage = (ETMPx – 512) • 1.5mV
0 = thermal shutdown has not occurred; 1 = thermal shutdown has occurred
Status cleared to ‘0’ on read of Thermal Register Group
Device revision code
Temperature measurement voltage = (ITMP – 512) • 1.5mV = 8mV * T(°K)
Cyclic redundancy check (CRC) value
This reference voltage = (REF – 512) • 1.5mV. Normal range is within 2.1V to 2.9V
1 = turn off interrupts and clear flags for cell ‘x’
cell voltage for cell ‘x’ = (CxV – 512) • 1.5mV
reads as 0xFFF while A/D conversion in progress
0 = cell ‘x’ not flagged for undervoltage condition; 1 = cell ‘x’ flagged
0 = cell ‘x’ not flagged for overvoltage condition; 1 = cell ‘x’ flagged
UV
OV
comparison voltage
comparison voltage
LTC6803-1/LTC6803-3
25
680313f