Data Sheet
GE
CAR1212DC series DC-DC converter
Input: -36VD C to -75VDC; Output: 12VDC @ 1200W; 3.3VDC or 5 VDC @ 1A
Standard READ: Up to two bytes of data may follow a READ
PMBusTM Command set:
request depending on the required data content. Analog data is
always transmitted as LSB followed by MSB. PEC is optional and
includes the address and data fields.
Hex Data Write
Code Byte
01
02
03
10
Command
Operation
ON_OFF_config
Clear_faults
Function
Output ON/OFF
1
1
0
1
W
1
S
7
1
Wr
1
A
8
1
A
Clear Status
Write control
Slave address
Command Code
Write_protect
W
W
1
7
1
Rd
1
A
8
LSB
1
A
Store_default_all
11
0
Store permanently
Reset defaults
Vout constants
Set Vout
RPM or duty cycle
Set fan speed
Set OV fault limit
Latch only
Set OV warn limit
Latch, restart,
folddown
Sr Slave Address
Restore_default_all
Vout_mode
Vout_command
12
20
21
3A
3B
40
41
42
47
0
1
2
1
2
2
1
2
1
8
MSB
1
A
8
PEC
1
1
P
W
W
W
W
No-ack
Fan_config_1_2
Fan_command_1
Vout_OV_fault_limit
Vout_OV_fault_response
Vout_OV_warn_limit
Iout_OC_fault_response
Block instruction: When writing or reading more than two bytes of
data at a time BLOCK instructions for WRITE and READ commands
must be used instead of the Standard Instructions.
W
W
Block write format:
1
S
7
1
Wr
1
A
8
1
A
Slave address
Command Code
W
W
W
W
Set OC warn limit
Iout_OC_warn_limit
OT_fault_limit
4A
4F
50
2
2
1
Set OT fault limit
Latch, restart
8
1
A
8
1
A
8
1
A
OT_fault_response
Byte count = N
Data 1
Data 2
Set OT warn limit
OT_warn_limit
Status_byte
Status_word
Status_Vout
Status_Iout
Status_input
Status_temperature
Status_CML
51
78
79
7A
7B
7C
7D
7E
80
2
1
2
1
1
1
1
1
1
8
……….
1
A
8
1
A
8
PEC
1
A
1
P
Data 48
Block read format:
1
S
7
1
Wr
1
A
8
1
A
Slave address
Command Code
1
Sr
7
1
Rd
1
A
Status_mfr_specific
Slave Address
Status_fan_1_2
Read_Vout
Read_Iout
Read_temperature_1
PMBus revision
81
8B
8C
8D
98
1
2
2
2
1
Read Vout
Read Iout
Read Temperature
8
1
A
8
1
A
8
1
A
Byte count = N
Data 1
Data 2
8
……….
1
A
8
1
A
8
PEC
1
1
P
Read fan_speed
Mfr_ID
90
99
9A
9B
9C
2
5
Read speed in RPM
FRU_ID
Data 48
NoAck
Mfr_model
Mfr_revision
Mfr_location
16
4
Linear Data Format The definition is identical to Part II of the
PMBus Specification. All standard PMBus values, with the exception
of output voltage related functions, are represented by the linear
format described below. Output voltage functions are represented
by a 16 bit mantissa. Output voltage has a E=9 constant exponent.
4
Mfr_date
Mfr_serial
Mfr_Vin_min
Mfr_Vin_max
Mfr_Iin_max
Mfr_Pin_max
Mfr_Vout_min
Mfr_Vout_max
Mfr_Iout_max
Mfr_Pout_max
Mfr_Tambient_max
Mfr_Tambient_min
FRW_revision
9D
9E
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
D0
6
15
2
The Linear Data Format is a two byte value with an 11-bit, two’s
complement mantissa and a 5-bit, two’s complement exponent or
scaling factor, its format is shown below.
36V (linear format)
75V (linear format)
40A (linear format)
1400W (linear format)
10V (linear format)
15V (linear format)
100A (linear format)
1200W (linear format)
70C (linear format)
-10C (linear format)
2
2
2
2
2
2
2
2
Data Byte High
Data Byte Low
Bit
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Exponent (E)
Mantissa (M)
The relationship between the Mantissa, Exponent, and Actual Value
(V) is given by the following equation:
2
1
V = M ∗ 2E
Fan_duty_cycle_ I2C
OTF_RECOVERY_I2C
D6
E5
1
2
Where:
Duty_cycle read in %
Recovery
hysteresis °C
V is the value
M is the 11-bit, two’s complement mantissa
E is the 5-bit, two’s complement exponent
DCOKHI_ I2C
DCOKLO_ I2C
E6
E7
2
2
(1/512V)
(1/512V)
October 21, 2013
©2013 General Electric Company. All rights reserved.
Page 11
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