TS1100 TOUCHSTONE [Touchstone Semiconductor Inc], TS1100 Datasheet - Page 7

• Manufacturer Part Number: TS1100
• Description: A 1uA, +2V to +25V SOT23 Precision Current-Sense Amplifier
• Manufacturer: TOUCHSTONE [Touchstone Semiconductor Inc]

The internal configuration of the TS1100 – a
unidirectional high-side, current-sense amplifier - is
based on a commonly-used operational amplifier (op
amp) circuit for measuring load currents (in one
direction) in the presence of high-common-mode
voltages. In the general case, a current-sense
amplifier monitors the voltage caused by a load
current through an external sense resistor and
generates an output voltage as a function of that load
current. Referring to the typical application circuit on
Page 1, the inputs of the op-amp-based circuit are
connected across an external RSENSE resistor that
is used to measure load current. At the non-inverting
input of the TS1100 (the RS+ terminal), the applied
voltage is I
the non-inverting input of the internal op amp, op-amp
feedback action forces the inverting input of the
PIN FUNCTIONS
BLOCK DIAGRAM
DESCRIPTION OF OPERATION
TS1100DS r1p0
LOAD
x RSENSE. Since the RS- terminal is
SOT23
PIN
1, 2
5
4
3
LABEL
GND
OUT
RS+
RS-
External Sense Resistor Power-Side Connection
External Sense Resistor Load-Side Connection
Ground. Connect these pins to analog ground.
Output Voltage. V
OUT
is proportional to V
internal
(I
RSENSE (V
(at the RS+ terminal) are equal. To minimize any
additional error because of op-amp input bias current
mismatch, both R
Since the internal p-channel FET’s source is
connected to the inverting input of the internal op
amp and since the voltage drop across R
same as the external V
drives the gate of the FET such that the FET’s drain-
source current is equal to:
FUNCTION
LOAD
x RSENSE). Therefore, the voltage drop across
op
SENSE
amp
) and the voltage drop across R
GAIN
SENSE
s are the same value.
S
SENSE
= V
to
V
R
RS+
SENSE
GA N
, op amp feedback action
the
- V
RS-
TS1100
same
GAIN
potential
Page 7
RTFDS
is the
GAIN