© 2023
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WHY5640 TEMPERATURE CONTROLLER
Table 2. WHY5690 Evaluation Board Pin Descriptions
SILKSCREEN
LABEL
NAME
FUNCTION
LIMA
Limit A Trimpot
Sets the maximum output current drawn from the V
S
supply input and delivered to
OUTPUTA. This is heating current limit when used with NTC sensors.
LIMB
Limit B Trimpot
Sets the maximum output current drawn from the V
S
supply input and delivered to
OUTPUTB. This is cooling current limit when used with NTC sensors.
P GAIN
Proportional Gain
Sets the proportional gain constant for the control loop and can be adjusted to optimize
the control parameters of the system using the P GAIN trimpot. Turning the trimpot
counter-clockwise will increase the value, while turning it clockwise will decrease the
value.
I TERM
Integrator Time
Constant
Sets the integrator time constant for the control loop and can be adjusted to optimize
the control parameters of the system using the I TERM trimpot. Turning the trimpot
counter-clockwise will decrease the value, while clockwise will increase the value.
RSET
Setpoint
Resistance Trimpot
Sets the resistance value of the thermistor at the desired operating temperature. The
resistance can be monitored using the two test points (see
) while turning the
trimpot. The RSET switch needs to be in the SET position while setting the resistance.
RSET SWITCH
Run / Set Switch
Sets whether the evaluation board is running (RUN position) or parameters are being
set (SET position). When adjusting the RSET trimpot, the RSET switch must be in the
SET position. Once the resistance is set, the switch can be moved to the RUN position.
Positive connection to the sensor.
SENSOR-
Sensor -
Negative connection to the sensor.
OUTPUTA
Output A
Connect OUTPUTA to the negative terminal on your thermoelectric when controlling
temperature with Negative Temperature Coefficient thermistors. OUTPUTA provides
the heating current to the TEC for NTC sensors. Connect OUTPUTA to the positive
thermoelectric terminal when using Positive Temperature Coefficient RTDs. Resistive
heaters can be connected either way for quick connection. See
for output
configuration for maximum voltage connection.
OUTPUTB
Output B
Connect OUTPUTB to the positive terminal on your thermoelectric when controlling
temperature with Negative Temperature Coefficient thermistors. OUTPUTB provides
the cooling current to the TEC for NTC sensors. Connect OUTPUTB to the negative
thermoelectric terminal when using Positive Temperature Coefficient RTDs. Resistive
heaters can be connected either way for quick connection. See
for output
configuration for maximum voltage connection.
VS
Power Drive
Supply Input
Provides power to the WHY5640 H-Bridge Power Stage. Supply range input for this
pin is +4.5 to +30 VDC. The maximum current drain on this terminal should not exceed
2.5 A.
VDD
Control Electronics
Supply Input
Power supply input for the WHY5640’s internal control electronics. Supply range input
for this pin is +5 to +26 VDC.
PGND
Power Drive
Supply Ground
Connect the V
S
power supply ground connection to PGND. Pin 11 (PGND) and Pin 12
(CGND) are internally connected on the WHY5640.
VM1 & VM2
Voltage Monitor 1
& 2
Provides monitor voltages referenced to the COM terminal. Externally monitor the
WHY5640 setpoint resistance and the actual temperature sensor resistance levels by
monitoring voltages produced from the sensor bridge circuit. VM1 and VM2 can be
used to calculate the thermistor resistance using
Equation 7.
COM
Common
Reference monitor voltages to this Common terminal. Do not connect the power supply
ground to this terminal.
ENABLE ON/OFF
Enable on / off
switch
Enables and disables the WHY5640 output current. The green ON LED indicator will
light when the output current is enabled. ENABLE switch should be set to the OFF
position when connecting power to the WHY5690 Evaluation Board.
