DRV590_16 Datasheet, PDF (8/18 Pages) Texas Instruments – 1.2-A HIGH-EFFICIENCY PWM POWER DRIVER

DRV590
SLOS365A – AUGUST 2001 – REVISED AUGUST 2002
APPLICATION INFORMATION
driving TEC elements
Below is a typical application schematic.
J5
J4
IN– (VCOM) IN+
J1
R3
120 kΩ
J8
VDD
R4
120 kΩ
J2
R1
1 kΩ
R2
1 kΩ
R5
120 kΩ
J3
C3
1 µF
NC
IN+
IN–
SHUTDOWN
GAIN0
GAIN1
PVDD
OUT+
NC
PGND
NC
AREF
AGND
COSC
ROSC
VDD
PVDD
OUT–
NC
PGND
L1
10 µH
C5
10 µF
L2
10 µH
C4
1 µF
C9
220 pF
R6
120 kΩ
C1
1 µF
C2
1 µF
C8
10 µF
J8
VDD
J9
GND
J7
OUT+
C6
10 µF
C7
10 µF
J6
OUT–
output filter considerations
TEC element manufacturers provide electrical specifications for maximum dc current and maximum output
voltage for each particular element. The maximum ripple current, however, is typically only recommended to
be less than 10%. The maximum temperature differential across the element decreases as ripple current
increases and can be calculated using equation 1.
DT + _{(1 ) N2)} ¹ _DTmax
(1)
∆T = actual temperature differential
∆T_max = maximum temperature differential (specified by manufacturer)
N = ratio of ripple current to dc current
According to this relationship, a 10% ripple current reduces the maximum temperature differential by 1%. A LC
network may be used to filter the current flowing to the TEC to reduce the amount of ripple and, more importantly,
protect the rest of the system from any electromagnetic interference (EMI).
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