Hardware
6
SLYU051A – August 2019 – Revised March 2020
Copyright © 2019–2020, Texas Instruments Incorporated
TMCS1101EVM
3.2
Circuitry
This section summarizes the TMCS1101EVM components.
For the following circuits:
•
x = B for bidirectional, or U for unidirectional
•
y = A to D for the A1 to A4 gain variants, respectively.
3.2.1
Bypass Capacitors
C1xy and C2xy are 10-
μ
F and 0.1-
μ
F supply bypass capacitors, respectively, for the TMCS1101. C4xy is
the 0.1-
μ
F bypass capacitor for the optional temperature sensor.
3.2.2
Output Filter
C3xy and R1xy are footprints for the optional output filter. Default values are 10 pF and 0
Ω
, but no
capacitors are installed. TP2xy is the test point for the TMCS1101 output.
3.2.3
Measurement Connector
J2x is an additional connector for measuring VCC and VOUT. J2x also provides a connection for
measuring board temperature (TMP).
3.2.4
Load Connectors
T1xy and T2xy correspond to the high-current rated load connectors. By default, the EVM is only
populated with two of these connectors on the bidirectional, lowest gain variant (x = B and y = A). TP3x
and TP6x are Kelvin connections to probe the EVM inputs. The IS+ (T1xy) and IS– (T2xy) 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 (TP2xy). 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 TMCS1101 data sheet.
3.2.5
Ground Test Points
TP3x, TP4x, and TP5x correspond to ground connections of the TMCS1100 device.
3.2.6
TMCS1101 Isolated Current-Sense Amplifier
U1xy is the TMCS1101 isolated current-sense amplifier. Eight segments are supplied within the
TMCS1101EVM board. Each segment is populated with one of the available device gains for bidirectional
or unidirectional sensing. This configuration enables users to test the devices and determine the best gain
setting for a given application. For y = A to D, the gain is 50 mV/A, 100 mV/A, 200 mV/A, and 400 mV/A,
respectively.
•
The TMCS1101AnB is used for bidirectional applications, while TMCS1101AnU is used for
unidirectional applications (where n = 1 to 4 for the A1 to A4 gain variants, respectively).
•
A magnetic field is generated based on the load current that is connected across the inputs IS+ and
IS–, and flows through the TMCS1101 leadframe.
•
The output voltage swing limitation and required load current sensing range are the key factors when
determining device selection.
•
The selected device must allow the output voltage to remain within the acceptable range after the load
current is transduced and amplified by the respective device gain. The max output voltage must remain
within the range of 25 mV above ground to 100 mV below the supply voltage.
•
Choose an appropriate gain to create the largest appropriate output swing, and to minimize error.
3.3
Temperature Sensor
U2x is a temperature sensor that is not required for TMCS1100 operation. However, U2x provides the
option of measuring board temperature for determining ambient conditions.
