LTC6803 Просмотр технического описания (PDF) - Linear Technology

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Компоненты Описание

производитель

LTC6803

Multicell Battery Stack Monitor

Linear Technology 

LTC6803-1/LTC6803-3

OPERATION

CSBI

SCKI

SDI

Sn

(n = 1 TO 12)

WRCFG + CFGR + PEC

td td < 2µs IF Sn IS UNLOADED

Sn, DISCHARGE PIN STATE

680313 F08

Figure 8. S Pin Action and SPI Transmission

Read Cell Voltage Registers (12 Cell Mode)

1. Pull CSBI low

2. Send RDCV command and PEC

3. Read CVR00 byte of bottom device, then CVR01 (B), CVR02 (B), … CVR17 (B), and then PEC (B)

4. Read CVR00 byte of middle device, then CVR01 (M), CVR02 (M), … CVR17 (M), and then PEC (M)

5. Read CVR00 byte for top device, then CVR01 (T), CVR02 (T), … CVR17 (T), and then PEC (T)

6. Pull CSBI high

Calculation of serial interface time for sequence above:

Number of devices in stack = N

Number of bytes in sequence = B = 2 command byte, and 18 data bytes plus 1 PEC byte per device = 2 + 19 • N

Serial port frequency per bit = F

Time = (1/F) • B • 8 bits/byte = (1/F) • (2 + 19 • N) • 8

Time for 3-cell example above, with 1MHz serial port = (1/1000000) • (2 + 19 • 3) • 8 = 472µs

Start Cell Voltage ADC Conversions and Poll Status (Toggle Polling)

1. Pull CSBI low

2. Send STCVAD command byte and PEC (all devices in stack start ADC conversions simultaneously)

3. SDO output from bottom device pulled low for approximately 12ms

4. SDO output toggles at 1kHz rate, indicating conversions complete for all devices in daisy chain

5. Pull CSBI high to exit polling

Start Cell Voltage ADC Conversions and Poll Status (Broadcast Command with Toggle Polling)

1. Pull CSBI low

2. Send STCVAD command and PEC (all devices in stack start ADC conversions simultaneously)

3. SDO output of all devices in parallel pulled low for approximately 12ms

4. SDO output toggles at 1kHz rate, indicating conversions complete for all devices in the daisy chain

5. Pull CSBI high to exit polling

Poll Interrupt Status (Level Polling)

1. Pull CSBI low

2. Send PLINT command and PEC

3. SDO output from bottom device pulled low if any device has an interrupt condition; otherwise, SDO high

4. Pull CSBI high to exit polling

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