Rainbow Electronics MAX16066 User Manual
Page 18
12-Channel/8-Channel, Flash-Configurable System
Managers with Nonvolatile Fault Registers
MAX16065/MAX16066
18 _____________________________________________________________________________________
are MON1/MON2, MON3/MON4, MON5/MON6, MON7/
MON8, MON9/MON10, MON11/MON12 with the first
input always being at a higher voltage than the second.
Use differential voltage sensing to eliminate voltage off-
sets or measure supply current. See Figure 4. In differ-
ential mode, the odd-numbered MON_ input measures
the absolute voltage with respect to GND while the result
of the even input is the difference between the odd and
even inputs. See Figure 4 for the typical differential mea-
surement circuit.
Internal Current-Sense Amplifier
The current-sense inputs, CSP/CSM, and a current-
sense amplifier facilitate power monitoring (see Figure
5). The voltage on CSP relative to GND is also monitored
by the ADC when the current-sense amplifier is enabled
with r47h[0]. The conversion results are located in regis-
ters r19h and r1Ah (see Table 10). There are two select-
able voltage ranges for CSP set by r47h[1], see Table
8. Although the voltage can be monitored over SMBus
or JTAG, this voltage has no threshold comparators and
cannot trigger any faults. Regarding the current-sense
amplifier, there are four selectable ranges and the ADC
output for a current-sense conversion is:
X
ADC
= (V
SENSE
x A
V
)/1.4V x (2
8
- 1)
where X
ADC
is the 8-bit decimal ADC result in register
r18h, V
SENSE
is V
CSP
- V
CSM,
and A
V
is the current-
sense voltage gain set by r47h[3:2].
In addition, there are two programmable current-sense
trip thresholds: primary overcurrent and secondary over-
current. For fast fault detection, the primary overcurrent
threshold is implemented with an analog comparator
connected to the internal OVERC signal. The OVERC
signal can be output on one of the GPIO_s. See the
General-Purpose Inputs/Outputs section for configur-
ing the GPIO_ to output the OVERC signal. The primary
threshold is set by:
I
TH
= V
CSTH
/R
SENSE
where I
TH
is the current threshold to be set, V
CSTH
is the
threshold set by r47h[3:2], and R
SENSE
is the value of
the sense resistor. See Table 8 for a description of r47h.
OVERC depends only on the primary overcurrent thresh-
old. The secondary overcurrent threshold is implement-
ed through ADC conversions and digital comparison set
by r6Ch. The secondary overcurrent threshold includes
programmable time delay options located in r73h[6:5].
Primary and secondary current-sense faults are enabled/
disabled through r47h[0].
General-Purpose Inputs/Outputs
GPIO1
–
GPIO8 are programmable general-purpose
inputs/outputs. GPIO1–GPIO8 are configurable as a
manual reset input, a watchdog timer input and output,
logic inputs/outputs, fault-dependent outputs. When pro-
grammed as outputs, GPIO_s are open drain or push-
pull. See Tables 12 and 13 for more detailed information
on configuring GPIO1
–
GPIO8.
Figure
4. Differential Measurement Connections
Figure
5. Current-Sense Amplifier
MAX16065
MAX16066
I
LOAD
LOAD
MON
ODD
MON
ODD
MON
EVEN
MON
EVEN
R
S
POWER
SUPPLY
POWER
SUPPLY
+
-
+
+
-
-
*A
V
CS+
CS-
*V
CSTH
*ADJUSTABLE BY r47h[1:0]
R
SENSE
TO ADC MUX
V
MON
LOAD
OVERC
MAX16065