TS1101 TOUCHSTONE [Touchstone Semiconductor Inc], TS1101 Datasheet - Page 7

• Manufacturer Part Number: TS1101
• Description: A 1uA, +2V to +25V Bidirectional Precision Current-Sense Amplifier
• Manufacturer: TOUCHSTONE [Touchstone Semiconductor Inc]

PIN FUNCTIONS
BLOCK DIAGRAM
DESCRIPTION OF OPERATION
The internal configuration of the TS1101 – a
bidirectional high-side, current-sense amplifier – is a
variation of the TS1100 uni-directional current-sense
amplifier. In the design of the TS1101, the input
amplifier was reconfigured for fully differential
input/output operation and a second low-threshold p-
channel FET (M2) was added where the drain
terminal of M2 is also connected to ROUT.
Therefore, the behavior of the TS1101 for when
V
Referring to the typical application circuit on Page 1,
the inputs of the TS1101’s differential input/output
amplifier are connected across an external RSENSE
TS1101DS r1p0
RS-
PIN
1
2
3
4
5
6
> V
RS+
LABEL
SIGN
GND
OUT
VDD
RS+
RS-
is identical for when V
Ground. Connect this pin to analog ground.
Comparator Output, push-pull; SIGN is HIGH for (V
Output Voltage. V
External Sense Resistor Load-Side Connection
SIGN Comparator External Power Supply Pin; Connect this pin to system’s logic VDD supply.
External Sense Resistor Power-Side Connection
RS+
OUT
> V
is proportional to V
RS-
.
SENSE
FUNCTION
resistor that is used to measure current. At the non-
inverting input of the TS1101 (the RS- terminal), the
applied voltage is I
terminal is the non-inverting input of the internal op
amp, op amp feedback action forces the inverting
input of the internal op amp to the same potential
(I
across RSENSE (V
voltage drop across RGAINA (at the RS+ terminal)
are equal. Necessary for gain ratio match, both
RGAINA and RGAINB are the same value.
Since p-channel M1’s source is connected to the
inverting input of the internal op amp and since the
voltage drop across RGAINA is the same as the
LOAD
= (V
x RSENSE). Therefore, the voltage drop
RS+
RS+
- V
> V
RS-
RS-
) or (V
) and LOW for (V
LOAD
SENSE
RS-
x RSENSE. Since the RS-
- V
= V
RS+
).
RS+
TS1101
RS-
- V
> V
RS-
RS+
) and the
).
Page 7
RTFDS