ACT4910QW
Rev 1.0, 15-Sept-2017
CMI 122: ACT4910QW122
CMI 121 is designed for standard 12V applications. CMI 121 default settings are appropriate for most typical applications.
It provides the 900kHz buck switching frequency to compromise size and efficiency. The default storage voltage is 36V
which allows for maximum capacitor energy storage. Placing a resistor between BSET and VSS can program the default
storage voltage to a lower value. Table 11 shows the default register settings.
Table 11: CMI 122 Default Register Settings
Function
Value
PLI & VOUT OK
32ms
Register
0x19h
Register Settings
PLI_FUNC_SEL[1:0] = 11
HMON_TSET[3:0] = 0100
HMON_THR[3:0] = 1011
EN_OV_REF[2:0] = 010
EN_STARTDELAY = 0
EN_LATCH_SPLMNT = 1
BST_CLIM[1:0] = 10
PLI Pin Function
Health Monitor Time
Health Monitor Threshold
Enable Overvoltage Reference
Startup Delay
0x1Fh
0x20h
0x20h
0x20h
0x21h
0x21h
0x21h
0x26h
0x28h
97.2%
0.92V
0ms
Latch Supplement Mode
Boost Current Limit
Yes
950mA
36V
Boost Voltage
BST_VSET[4:0] = 11111
BK_CLIM[1:0] = 11
Buck Peak Current Limit
Buck Switching Frequency
9A
900kHz
BK_FREQ[2:0] = 110
I2C Address
The CMI 122 7-bit I2C address is 0x5Ah. This results in 0xB4h for a write address and 0xB5h for a read address.
Device ID
The CMI 122 Device ID (register 0x3Bh) = 0x03h. This can be used to distinguish between different CMI versions.
Autonomous ADC Supervisory Function
The autonomous ADC supervisory function is disabled by default. All undervoltage register value are set to 0x00h and
all overvoltage register values are set to 0xFFh.
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