Hardware
6
SBOU209A – August 2019 – Revised March 2020
Copyright © 2019–2020, Texas Instruments Incorporated
TMCS1100EVM
3.2
Circuitry
This section summarizes the TMCS1100EVM components. For the following circuits, x = A to D for the A1
to A4 gain variants, respectively.
3.2.1
Bypass Capacitors
C1x and C2x are 10-
μ
F and 0.1-
μ
F supply bypass capacitors, respectively, for the TMCS1100. C5x is the
0.1-
μ
F bypass capacitor for the optional temperature sensor. C6x is the 0.1-
μ
F bypass capacitor for the
optional buffer amplifier.
3.2.2
Output Filter
C3x and R1x are footprints for the optional output filter. Default values are 0
Ω
and 10 pF. However, no
capacitors are installed. TP2x is the test point for the TMCS1100 output.
3.2.3
VREF Input Filter
C4x and R2x are footprints for the optional VREF input filter. Default values are 0
Ω
and 10 pF. However,
no capacitors are installed. TP3x serves as a test-point for the filtered input to the TMCS1100 VREF pin
while TP7x serves as a test point for the prefiltered input to the TMCS1100 VREF pin. J1x is a jumper that
conveniently allows the TMCS1100 reference to be shorted to ground, connected directly to an external
power supply, or shorted to a voltage set by a buffered voltage divider.
3.2.4
Buffer Amplifier Filter and Divider
C7x and R3x serve as a low-pass filter to the buffer amplifier. R3x and R4x serve as a voltage divider to
set the buffered voltage input to the TMCS1100 VREF pin. R5x serves as short that connects the voltage
divider directly to VREF SOURCE. R5x is left open and unpopulated by default.
3.2.5
Measurement Connector
J2x is an additional connector for measuring VREF Source, VCC, and VOUT. J2x also provides a
connection for measuring board temperature (TMP).
3.2.6
Load Connectors
T1x and T2x correspond to the high-current rated load connectors. By default, the EVM is only populated
with two of these connectors on the lowest gain variant A1, x = A. The IS+ (T1x) and IS– (T2x) inputs
accept a load that is converted to a magnetic field sensed by a Hall element that produces a voltage. This
voltage is amplified by the selected device gain and is presented at the VOUT test point (TP2x). The
acceptable load input maximum is 20 A for dc measurements. However, the load can be significantly
higher for ac signals, and the load is bound by the safe operating area (SOA) described in the TMCS1100
data sheet.
3.2.7
Ground Test Points
TP4x, TP5x, and TP6x correspond to ground connections of the TMCS1100 device.
3.2.8
TMCS1100 Isolated Current-Sense Amplifier
U1x is the TMCS1100 isolated current-sense amplifier. Four gain-option segments are supplied within the
TMCS1100EVM board. Each segment is populated with one of the available device gains. This
configuration enables users to test the devices and determine the best gain setting for a given application.
For x = A to D, the gain is 50 mV/A, 100 mV/A, 200 mV/A, and 400 mV/A, respectively.
•
The TMCS1100 can be used for both unidirectional and bidirectional applications.
•
A magnetic field is generated based on the load current that is connected across the inputs IS+ and
IS–, and flows through the TMCS1100 leadframe.
•
The output voltage swing limitation and required load current sensing range are the key factors when
determining device selection.