ltc4151 Linear Technology Corporation, ltc4151 Datasheet - Page 7

• Manufacturer Part Number: ltc4151
• Description: High Voltage I2c Current And Voltage Monitor
• Manufacturer: Linear Technology Corporation

BLOCK DIAGRAM
OPERATION
The LTC4151/LTC4151-1 accurately monitor high side cur-
rent and voltages. These devices accept a wide range of
input voltages from as low as 7V up to 80V and consume
less than 1.7mA quiescent current in normal operation. A
shutdown mode is available with the LTC4151 to reduce
the quiescent current to less than 300μA by pulling the
SHDN pin below 1V.
In default continuous scan mode after power-up, the
onboard 12-bit analog-to-digital converter (ADC) continu-
ously and sequentially measures the differential voltage
between SENSE
an internal sense amplifi er, the input voltage V
102.4V) through an internal voltage divider, and the voltage
applied to the ADIN pin (full-scale 2.048V). The reference
voltage of the ADC is internally set to 2.048V. The digital data
obtained by the ADC is stored in the onboard registers.
V
IN
+
and SENSE
2
9
V
735k
15k
IN
GND
INTERNAL
POWER
–
(full-scale 81.92mV) through
1
+
SENSE
25X
R
5
S
+
ADIN
10
–
SENSE
MUX
–
IN
(full-scale
6.3V
5μA
SHUTDOWN
In snapshot mode, the LTC4151/LTC4151-1 can perform
on-demand measurement of a selected voltage without
the need of continuous polling by a master controller. The
snapshot mode is enabled by programming the control
register through the I
register monitors the ADC’s conversion. When the conver-
sion is completed, the 12-bit digital code of the measured
voltage is held in the corresponding data registers.
The LTC4151/LTC4151-1 provide an I
the ADC data from the data registers and to program the
control register. Two three-state pins, ADR0 and ADR1,
are used to decode nine device addresses (see Table 1).
The LTC4151 features a single SDA pin to handle both
input data and output data, while the LTC4151-1 provides
separate SDAI (input) and SDAO (inverted output) pins to
facilitate optoisolation.
CONTROL
12-BIT ADC
8
V
REF
SHDN
(LTC4151)
= 2.048V
LTC4151/LTC4151-1
3
REGISTERS
DECODER
ADR1
2
I
C interface. A status bit in the data
2
C/
4
ADR0
6V
6V
2
C interface to read
(LTC4151-1)
LTC4151-1)
(LTC4151/
SDA/SDAI
SDAO
41511 BD
SCL
7
6
8
41511f
7