AMC7834 Datasheet, PDF (48/93 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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7.4.2 Closed-Loop Mode
In closed-loop mode the current sensors and bipolar DACs operate as four independent closed-loop current
controllers. In closed-loop operation, four autonomous closed-loop current controllers are implemented by
continuously adjusting the bipolar DAC outputs in response to the current-sense amplifier outputs.
Table 7 lists the typical register configurations for closed-loop mode.
Table 7. Closed-Loop Mode Register Configuration
REGISTER SETTING
LOOP-EN
CS-FILTER[2:0]
ADCINTn
LOOPn-SET[3:0]
DACn-SYNC
ADCINT/CS-SELECT
DACnnLOOP-ALARMEN
DACn-HIGH-ALARM
ADCINTn-DATA[11:0]
CSn-DATA[11:0]
DACn-DATA[11:0]
CLOSEDLOOPn[11:0]
DACnn-UP-THRES[11:0]
REGISTER ADDRESS
0x10
0x10
0x12
0x14
0x15
0x1B
0x1B
0x1E
0x20 to 0x23
0x28 to 0x2B
0x30 to 0x33
0x38 to 0x3B
0x4E to 0x4F
COMMENT
Set to 1
Configurable
Set to 1
Configurable
Unused
Set to 0
Configurable
Used
Readable
Unused
Unused
Configurable
Configurable
Figure 63 shows a typical analog implementation of a closed-loop current controller.
V(DRAIN)
Current Sense
Amplifier
R(SENSE)
DAC
+
Gate Drive
Amplifier
PA FET
Figure 63. Analog Closed-Loop Current Controller
Although the analog current controller is capable of setting and maintaining a given drain current (and therefore,
gain) through a PA FET it lacks the flexibility to scale easily to a large variety of FETs. The AMC7834
implements four closed-loop current controllers as a digital system thus giving it higher flexibility while satisfying
or improving on the specifications given by a typical analog closed-loop current controller.
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