Datasheet

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REV.: 0/2019 P-5
Reference Design
Specifi cations (measured @ Ta= 25°C, full load after warm up unless otherwise stated)
R-REF04-RIA12
FB1
V DD
1
1
SD
2
2
TIMER
3
3
V SS
4
BASE
5
FB
6
OUT
7
GATE
8
U1
D3
D1
1
2
C1
GND GND
R6
R7
2
1
HTSK1
Q1
R4
D2
R3
1
2
C2
GND
C14
GND
C8
GND
2 1
4 3
L1
2 1
4 3
L2
C9
1
2
C3
1
2
C4 C11
FB2
FB3
FB4
FB5
FB6
FB7
FB8
FB10
FB11
2 1
4 3
L 4
2 1
4 3
L5
GND
IN
-IN
-VIN
V IN
+VIN
1
CTRL
2
CASE
3
-VIN
4
-VOUT
5
-SENSE
6
TRIM
7
+SENSE
8
+VOUT
9
M1A
Mech Pin
10
Mech Pin
11
Mech Pin
12
Mech Pin
13
M1B
CTRL
+VIN
1
Gate In
2
Gate Out
3
-VIN
4
-VOU
5
-SENSE
6
T
T
T
RIM
7
+SENSE
8
+VOU
9
M2 A
Mech Pin
10
Mech Pin
11
Mech Pin
12
Mech Pin
13
Mech
Mech
Pin
14
Pin
15
M2B
V IN
-VIN
CTRL
+VIN
1
-VIN
2
CTRL
3
+VOUT
4
-VOUT
5
TRIM
6
M3
V IN
CTRL
-VIN
-VIN
3
CTRL
2
+VIN
1
-VOUT
4
-SENSE
5
TRIM
6
+SENSE
7
+VOUT
8
M4A
Mech Pin
9
Mech Pin
10
M4B
V IN
-VIN
CTRL
C15
R1 1
R1 2
GND
R8
R9
R10
GND
R1
R2
R5
C16
P1
C7 C10
C5 C6
-VOUT
-VOUT
-VOUT
+VOUT
+VOUT
+VOUT
+VOUT
CM
C
2
CMC 2
C
M
C
1
CMC
3
R13
R14
1
4
2 3
L3
1
2
4
3
U2
CTRL
-VIN
1
2
CON6
+VOUT
-VOUT
ENABLE
COO LINGFA N
ALTERN ATE PAR TS
MECHANICAL PINS
1
2
CON1
1
2
CON2
1
2
CON3
1 2
CON4
GND
1
2
CON5
1 2
FB9A
3 4
FB9B
1-2 3-4
FH1
TRIM
TRIM
TRIM
TRIM
1
2
CON7
-VOUT
CMC1
CMC3
IN
-IN
CASE
CA SE
F1
Surge Stopper Function
The converters are protected from high surge voltages with a clamp circuit based on LTC4366 surge stopper IC.
Voltage Clamping:
In normal operation, Q1 is forward biased. So the input voltage of the
converter is almost equal to the input voltage at CON1 (minus the diode
voltage drop of D1). In the case of a surge event on the input, Q1 enters
linear operation and clamps the voltage to a level which is preset by the
potential divider resistor chain R5 and R8 + R9 + R10.
Maximum Clamping Time:
The maximum clamping time is set by C15. It is preset to 30ms. The
time is related to capacitance by 311ms/µF. After this time the IC
shuts down Q1 to prevent thermal damage to of Q1. After 9 seconds
cool down period, U1 and Q1 enter normal operation again. Before
increasing the clamp time, always check the safe operating area of Q1.
The following clamp voltages are preset by jumpers on the board:
The clamp voltage can be adjusted to other levels by changing the
resistor chain using the following equation:
Inrush Current Limiter:
The clamp circuit also functions as an inrush current limiter for the on-board and off-board hold-up capacitors. It is not a classical inrush
current limiter, but rather a controlled ramp up of the capacitor voltage. Capacitor C14 is charged with a constant current of 20µA, so the
voltage ramps up linearly. The output voltage to the hold-up and fi lter capacitors tracks the voltage across C14. The voltage rise time is given
by the following equation:
C14 is populated with a 2n2 capacitor to give a voltage rise time (t
Vrise
) of 9V/ms. The inrush current can be calculated using:
The R-REF04-RIA12-1 has 3 x 150µF electrolytic caps fi tted, so C = 450µF
The R-REF04-RIA12-2 has 3 x 470µF electrolytic caps fi tted, so C = 1410µF
If external hold-up capacitance is added, the inrush current will increase proportionally. If the inrush current exceeds the supply capability,
then C14 should be increased to increase t
Vrise
.
Note: The current into C1 is not limited with this circuit.
Part
Number No Jumper set Jumper 1-2 Jumper 2-3
R-REF04-RIA12-1 160V 154V 103V
R-REF04-RIA12-2 75V 70V 36V
V
clamp
=
( R8 + R9 + R10 ) x 101.6µA +1.23V
I
Inrush
=
C x t
Vrise
I
Inrush
=
450 x 9V/ms
=
4A
I
Inrush
=
1410 x 9V/ms
=
12.7A
∆V
=
20µA
∆t
C
C14
FB1
V DD
1
1
SD
2
2
TIMER
3
3
V SS
4
BASE
5
FB
6
OUT
7
GATE
8
U1
D3
D1
1
2
C1
GND GND
R6
R7
2
1
HTSK1
Q1
R4
D2
R3
1
2
C2
GND
C14
GND
C8
GND
2 1
4 3
L1
2 1
4 3
L2
C9
1
2
C3
1
2
C4 C11
FB2
FB3
FB4
FB5
FB6
FB7
FB8
FB10
FB11
2 1
4 3
L 4
2 1
4 3
L5
GND
IN
-IN
-VIN
V IN
+VIN
1
CTRL
2
CASE
3
-VIN
4
-VOUT
5
-SENSE
6
TRIM
7
+SENSE
8
+VOUT
9
M1A
Mech Pin
10
Mech Pin
11
Mech Pin
12
Mech Pin
13
M1B
CTRL
+VIN
1
Gate In
2
Gate Out
3
-VIN
4
-VOU
5
-SENSE
6
T
T
T
RIM
7
+SENSE
8
+VOU
9
M2 A
Mech Pin
10
Mech Pin
11
Mech Pin
12
Mech Pin
13
Mech
Mech
Pin
14
Pin
15
M2B
V IN
-VIN
CTRL
+VIN
1
-VIN
2
CTRL
3
+VOUT
4
-VOUT
5
TRIM
6
M3
V IN
CTRL
-VIN
-VIN
3
CTRL
2
+VIN
1
-VOUT
4
-SENSE
5
TRIM
6
+SENSE
7
+VOUT
8
M4A
Mech Pin
9
Mech Pin
10
M4B
V IN
-VIN
CTRL
C15
R1 1
R1 2
GND
R8
R9
R10
GND
R1
R2
R5
C16
P1
C7 C10
C5 C6
-VOUT
-VOUT
-VOUT
+VOUT
+VOUT
+VOUT
+VOUT
CM
C
2
CMC2
C
M
C
1
CMC
3
R13
R14
1
4
2 3
L3
1
2
4
3
U2
CTRL
-VIN
1
2
CON6
+VOUT
-VOUT
ENABLE
COO LINGFA N
ALTERN ATE PARTS
MECHANICAL PINS
1
2
CON1
1
2
CON2
1
2
CON3
1 2
CON4
GND
1
2
CON5
1 2
FB9A
3 4
FB9B
1-2 3-4
FH1
TRIM
TRIM
TRIM
TRIM
1
2
CON7
-VOUT
CMC1
CMC3
IN
-IN
CASE
CA SE
F1