Operation - Linear Technology DC1659A Quick Start Manual

DEMO MANUAL DC1659A

OPERATION

Current Sense Gain
The gain of the LT6109 current sense amplifier is set
by the ratio of R
circuit this means that the gain is set by the ratio of
(R1 + R2 + R3)/R10. The gain error is primarily controlled
by the precision of the resistors used. The factory resis-
tors are a 1% tolerance which will dominate the gain
error. To reduce system gain error, the resistors can be
replaced with 0.1% resistors.
LED Indicators
The LEDs indicate the state of the comparator outputs.
When the LED is on, the comparator is latched low. When
the LED is off, the comparator output is high. When the
comparator output is latched low, the LT6109 must be reset
to refresh the comparator output and to turn off the LEDs.
Jumper Summary
Reset(JP1): The Reset jumper has two settings for manual
or auto mode. In manual mode, the user must press the
reset button to reset the latching comparators. In auto
mode, the comparators will be continuously reset every
10 seconds. The factory default setting is manual mode.
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and R resistors. In the demo
OUT IN
Optional Settings
1. For supply voltages below 3.3V, remove R20 and install
R21 (0Ω jumper). When R21 is installed, the supply
voltage must stay between 2.7V to 6V to prevent dam-
aging the TimerBlox ® circuitry that is used to reset the
comparator outputs.
2. To power the LT6109 from a supply separate from the
load, remove R22 and connect the power supply to V
turret.
3. There are a number of optional components that (not
installed) allow the DC1659 to be tailored to a specific
application:
A) To free comparator input INC1, remove R2 and R3
and install R19.
B) To free comparator input INC2, remove R1 and R2
and install R18.
C) To add filtering to the amplifier output, install C6.
4. R9 can be set to the same value as R10 to reduce error
caused by input bias current. Typically for values of
R10 (less than 1k) and R9 can be omitted as the error
is negligible.
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