AMC7834 Datasheet, PDF (28/93 Pages) Texas Instruments – AMC7834 12-Bit Integrated Power-Amplifier Monitor and Control System with Temperature, Current and Voltage Supervision Capabilities

AMC7834
SLAS972B – NOVEMBER 2014 – REVISED MARCH 2016
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Alternatively, with the AMC7834 set in closed-loop mode (LOOP-EN bit set to 1 in register 0x10) each bipolar
DAC output updates automatically in response to one of the four current sensors in the device (see the Closed-
Loop Mode section). In closed-loop mode the AMC7834 bipolar DACs operate as four autonomous closed-loop
current controllers.
The DAC upper threshold registers (address 0x4E through 0x4F) sets an upper output limit other than full-scale
for the bipolar DACs when operating in closed-loop mode. The upper threshold feature can be used to limit the
maximum output voltage for each bipolar DAC. When a closed-loop controller attempts to set its bipolar DAC to a
value exceeding the corresponding DAC upper threshold register, the DAC is updated with the threshold code
instead.
7.3.1.1.2 Auxiliary DACs (AUXDAC1, AUXDAC2, AUXDAC3, and AUXDAC4)
The output range for each auxiliary DAC can be independently set through the DAC Range register (address
0x16) to either 0 to 5 V or 2.5 to 7.5 V. The POR and clamp value of each of the auxiliary DACs is fixed to
AGND. The maximum and minimum outputs from these DACs cannot exceed AV_CC or be lower than AGND,
respectively. Figure 46 shows a high level block diagram of each auxiliary DAC.
AVCC
Serial Interface DAC Data Register
WRITE
READ
DAC
DAC
Buffer
Active
0
DAC
Register
Register
Resistor String
Output
Range
VO
DAC Trigger
0x000
1
Configuration
(synchronous
mode)
CLAMP MODE
(asynchronous mode)
DAC
output
CLAMP MODE
AGND
Figure 46. Auxiliary DAC Block Diagram
7.3.1.2 DAC Register Structure
The input data of the DACs is written to the individual DAC data registers (address 0x30 through 0x37) in straight
binary format for all output ranges (see Table 2).
DIGITAL CODE
0000 0000 0000
0000 0000 0001
1000 0000 0000
1111 1111 1110
1111 1111 1111
Table 2. DAC Data Format
0 TO 5 V RANGE
0
0.00122
2.5
4.99756
4.99878
DAC OUTPUT VOLTAGE (V)
2.5 TO 7.5 V RANGE
–4 TO 1 V RANGE
2.5
–4
2.50122
–3.99878
5
–1.5
7.49756
0.99756
7.49878
0.99878
–5 TO 0 V RANGE
–5
–4.99878
–2.5
–0.00244
–0.00122
28
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