DEMO MANUAL DC1902B
LT4320
Ideal Diode Bridge Controller
Description
Demonstration circuit 1902B features the ideal diode bridge
controller
LT
®
4320
suitable for applications that require
low to medium current AC to DC full-wave rectification
or DC polarity correction and a small compact solution
(see Table 2).
The LT4320 drives four N-channel MOSFETs to perform
full-wave rectification functionally similar to a diode bridge
but with much lower power dissipation. This topology eases
thermal design, and increases usable output voltage. In
addition, an all N-channel topology has benefits over a
P-channel topology such as a wider selection of MOSFETs,
lower cost, lower R
DS(ON)
, and smaller footprint.
Only a few essential components are required to oper-
ate the LT4320 as an ideal diode bridge: four N-channel
MOSFETs, a bypass ceramic capacitor, and an AC smooth-
ing capacitor (C
LOAD
). The DC1902B includes low R
DS(ON)
N-channel MOSFETs (10mΩ typical) to support low to
medium current applications. When an AC voltage source
is used, the onboard C
LOAD
(C2) capacitor allows for up
to 1.5A of average output current. Add additional C
LOAD
capacitance to support higher current AC applications. A
unidirectional TVS (D1) is included to protect the applica-
tion from brief overvoltage events up to the part rating. A
footprint for bidirectional TVS (D2) is also included and is
recommended for electrically harsh conditions.
Design files for this circuit board are available at
http://www.linear.com/demo
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
performance summary
Table 1. DC Efficiency of the DC1902B at Various Input Voltages
DC INPUT VOLTAGE (V)
12.046
20.045
40.025
DC OUTPUT VOLTAGE (V)
11.977
19.972
39.952
DC LOAD CURRENT (A)
3.500
3.500
3.500
EFFICIENCY (%) (TYPICAL)
99.43
99.64
99.82
dc1902bfa
1
DEMO MANUAL DC1902B
Quick start proceDure
1. Connect a DC or AC power supply to VIN1 and VIN2 in
any polarity as shown in Figure 1. Make sure the output
voltage of the DC or AC power supply is within the input
voltage range of the DC1902B as shown in Table 2.
2. Connect a load and a voltmeter across VOUT+ to VOUT–
as shown in Figure 1.
3. For a DC input, raise the output voltage of the DC power
supply to the desired level. Check the DC1902B output
voltage across VOUT+ to VOUT–. The reading should
be very close to the input voltage of the DC1902B.
4. For an AC input, raise the output voltage of the AC power
supply to the desired level. Make sure the load current
is within the current limits as shown in Table 2 with the
demo board supplied C
LOAD
(C2). Add additional C
LOAD
capacitance, if higher output load current is desired. With
an oscilloscope in place of the output voltmeter, make
sure the lowest point of the output voltage (droop) is
above the minimum operating voltage specified in the
LT4320 data sheet.
Note:
Maximum load current with an AC input should be
limited to about 3A due to MOSFET and PCB limitations.
Table 2. Maximum Load Current per Input Voltage and Type of Voltage Source
VOLTAGE SOURCE
DC
AC, 60Hz
AC, 60Hz
*Limited by demo board supplied C2.
INPUT VOLTAGE
9VDC to 60VDC
12VAC
RMS
24VAC
RMS
MAXIMUM LOAD CURRENT
3.5A
0.7A*
1.5A*
Figure 1. DC1902B Setup
2
dc1902bfa
DEMO MANUAL DC1902B
thermal plot
Figure 2. Ideal Diode Bridge Using Four PSMN011-60MS vs Diode Bridge Using Four B360B Passing 3ADC
(VIN1 Positive with Respect to VIN2)
dc1902bfa
3
DEMO MANUAL DC1902B
parts list
ITEM
1
2
3
4
1
2
3
4
5
6
7
QTY
1
1
1
4
1
0
4
1
1
1
4
REFERENCE
C1
C2
U1
Q1 TO Q4
D1
D2
E1 TO E4
J5
LED1
R1
MH1 TO MH4
PART DESCRIPTION
CAP, X7S, 1µF, 100V, 10% 0805
CAP, ALUM, 680µF 63V, C-SANYO-12.5X35
IC, LT4320IDD, DFN8DD
MOSFET, N-CH, 60V, LFPAK33
DIODE, TVS 400W, SMA-DIODE
DIODE, SMBJ60CA
TP, TURRET, 0.094"
CONN, POWER JACK 2.1X5.5MM HI CUR SMD
LED, GREEN SMD
RES, CHIP 3.9k, 5% 2512
STAND-OFF, NYLON 0.50" TALL
MANUFACTURER/PART NUMBER
TDK, C2012X7S2A105K
PANASONIC, EEU-FR1J681L
LINEAR TECHNOLOGY, LT4320IDD#PBF
NXP, PSMN011-60MS
DIODES INC, SMAJ60A-13-F
OPT
MILL-MAX, 2501-2-00-80-00-00-07-0
CUI INC, PJ-002A-SMT
ROHM, SML-010FTT86L
VISHAY, CRCW25123K90JNEG
KEYSTONE, 8833 (SNAP ON)
Required Circuit Components
Optional Circuit Components
4
dc1902bfa
5
4
3
2
1
REVISION HISTORY
ECO
__
1
E3
VOUT+
REBUILD WITH CHANGE
KAUGH H.
09-29-14
Q2
PSMN011-60MS
3
2
1
VOUT+
Q1
PSMN011-60MS
3
8
2
7
1
6
5
TG2
TG1
4
4
2
8
7
6
5
REV
DESCRIPTION
APPROVED
DATE
E1
schematic Diagram
D
VIN1
VIN1
D
TG2
1
C
12VAC - 24VAC
9VDC - 60VDC
1
8
IN1
5
9
DC INPUT = 3.5A
AC INPUT = 1.5A
LED1
GRN
C1
1uF
100V
D1
SMAJ60A
OUTP
D2
SMBJ60A
OPT
2
1
IN2
BG2
BG1
EP
OUTN
6
R1
3.9k
2512
63V
TG1
U1
LT4320IDD
7
3
2
+
C2
680uF
PANASONIC
EEU-FR1J681L
C
J5
PJ-002AH-SMT
3
4
5
6
7
8
Q3
PSMN011-60MS
4
5
6
7
8
1
2
3
Q4
PSMN011-60MS
BG2
1
2
3
B
4
BG1
B
E2
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
VOUT-
E4
VIN2
VIN2
VOUT-
CUSTOMER NOTICE
APPROVALS
KIM T.
KAUGH H.
A
NOTE: UNLESS OTHERWISE SPECIFIED
TECHNOLOGY
TITLE: SCHEMATIC
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
A
1. ALL CAPACITORS ARE IN MICROFARADS, 0805.
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
COMPACT IDEAL DIODE BRIDGE FULL WAVE RECTIFIER
SIZE
IC NO.
REV.
N/A
SCALE = NONE
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
4
LT4320IDD
DEMO CIRCUIT 1902B
DATE:
1
Monday, September 29, 2014
2
SHEET 1
1
OF 1
5
DEMO MANUAL DC1902B
dc1902bfa
5
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