MAX16031 Datasheet, PDF (19/42 Pages) Maxim Integrated Products – EEPROM-Based System Monitors with Nonvolatile Fault Memory

EEPROM-Based System Monitors
with Nonvolatile Fault Memory
Current Monitoring
The MAX16031 provides current-sense inputs CS+/CS-
and a current-sense amplifier for current monitoring
(see Figure 3). There are two programmable current-
sense thresholds: primary overcurrent and secondary
overcurrent. For fast fault detection, the primary over-
current threshold is implemented with an analog com-
parator connected to the OVERC output. The primary
threshold equation is:
I
TH
=
V_CSTH
R_SENSE
where I_TH is the current threshold to be set, V_CSTH is
the threshold set by r19h[1:0], and R_SENSE is the value
V_MON
CS+
CS-
R_SENSE
V_L
LOAD
-
+
MAX16031
TO ADC MUX
*AV
OVERC
*V_CSTH
*ADJUSTABLE BY r19h [1:0]
Figure 3. Current-Sense Block Diagram
of the sense resistor. See Table 4 for a description of
r19h. The ADC output for a current-sense conversion is:
( ) ^XADC ⁼
V_SENSE ×
V_RBP
A_V
×
2⁸ − 1
where X_ADC is the 8-bit decimal ADC result, V_SENSE is
V_CS+ - V_CS-, A_V is the current-sense voltage gain set
by r19h[1:0], and V_RBP is the reference voltage at RBP
(1.4V typical).
OVERC is latched when the primary overcurrent thresh-
old is exceeded by programming r5Ch[4]. The latch is
cleared by writing a ‘1’ to r53h[6]. OVERC depends
only on the primary overcurrent threshold. Other fault
outputs are programmed to depend on the secondary
overcurrent threshold. The secondary overcurrent
threshold is implemented through ADC conversions
and digital comparisons. The secondary overcurrent
threshold contains programmable time delay options
located in r5Ch[1:0]. Primary and secondary current-
sense faults are enabled/disabled through r1Bh[3].
Temperature Monitoring
The MAX16031 provides two sets of remote diode inputs,
DXP1/DXN1 and DXP2/DXN2, and one internal tempera-
ture sensor. The MAX16032 provides one set,
DXP1/DXN1, and one internal temperature sensor.
Calibration registers provide adjustments for gain and off-
set to accommodate different types of remote diodes.
The internal temperature sensor circuitry is factory
trimmed. In addition to offset/gain trimming, a program-
mable lowpass filter is provided. See Figure 4 for the
block diagram of the temperature sensor circuitry. The
remote diode is actually a diode-connected transistor.
See Application Notes AN1057 and AN1944 for informa-
tion on error budget and several transistor manufacturers.
Table 4. Overcurrent Primary Threshold and Remote Temperature Sense Gain Trim
REGISTER
ADDRESS
19h
4Fh
EEPROM
MEMORY
ADDRESS
99h
CFh
BIT RANGE
DESCRIPTION
[1:0]
[7:2]
[5:0]
[7:6]
Overcurrent Primary Threshold and Current-Sense Gain Setting:
00 = 200mV threshold, AV = 6V/V
01 = 100mV threshold, AV = 12V/V
10 = 50mV threshold, AV = 24V/V
11 = 25mV threshold, AV = 48V/V
Remote Temperature Sensor 1 Gain Trim. Note bit 6 is inverted.
Remote Temperature Sensor 1 Gain Trim
Not used
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