Preliminary Datasheet
R2A20124AFP/R2A20124ASP
Synchronous Phase Shift Full-Bridge Control IC Series
Description
R03DS0031EJ0300
Rev.3.00
Mar 11, 2011
The R2A20124AFP/R2A20124ASP controls a full-bridge phase shift circuit and secondary synchronous rectification.
The R2A20124AFP/R2A20124ASP has adjustable delay time functions which make ZVS of primary side and make
loss of body diode of primary switching device minimal.
The R2A20124AFP/R2A20124ASP is based on HA16163/R2A20121. And RAMP slope compensation circuit is built-
in as an additional function. Also its output driver circuits are improved to enlarge gate drive output voltage swing from
VREF to VCC.
In addition R2A20124AFP has ON/OFF function of synchronous rectification and includes amplifier which detect input
current signal.
Features
Maximum ratings
Supply voltage Vcc: 20 V
Operating junction temperature Tj-opr: –40 to +125°C
Electrical characteristics
VFB feedback voltage VFB(–): 1.25 V
2.0%
UVLO (Under Voltage Lockout) operation start voltage VH: 8.4 V
0.7 V
UVLO operation shutdown voltage VL: 8.0 V
0.6 V
UVLO hysteresis voltage dVUVL: 0.4 V
0.1 V
Output voltage swing of OUT-A, B, C, D, and E for gate drive: GND to VCC
Functions
R2A20124AFP/R2A20124ASP
Full-bridge phase-shift switching circuit with adjustable delay times
Pulse by pulse current limit
Synchronization I/O for the oscillator
Ramp sloping adjustor
Error amplifier built-in
Soft start function
R2A20124AFP
Synchronous rectification on/off control
Remote on/off control
Amplified output of current sense input voltage: CS
Package lineup
Pb-free LQFP-40: R2A20124AFP
Pb-free SOP-20: R2A20124ASP
Ordering Information
Part No.
R2A20124AFP-W0
R2A20124AFP-W5
R2A20124AFP-U0
R2A20124AFP-U5
R2A20124ASP-W0
R2A20124ASP-W5
R2A20124ASP-U0
R2A20124ASP-U5
Package Name
FP-40EV
Package Code
PLQP0040JB-C
Taping Spec.
2000 pcs./one taping product
2000 pcs./one taping product
—
—
2000 pcs./one taping product
2000 pcs./one taping product
—
—
FP-20DAV
PRSP0020DD-B
R03DS0031EJ0300 Rev.3.00
Mar 11, 2011
Page 1 of 12
R2A20124AFP/R2A20124ASP
Preliminary
Modified Points from R2A20121SP
The swing level of the maximum output voltage is changed from VREF to VCC.
Ramp sloping compensation circuit is added.
Synchronous rectification control is possible to turned off at light load. (only R2A20124AFP)
On/off control terminal for Remote is added. (only R2A20124AFP)
Illustrative Circuit
VIN
DC 12 V
DC 12 V
DC 12 V
DC 12 V
DC 12 V
Vbias
(DC 12 V)
VCC OUT OUT
-A
-B
SEC-CONT(∗
1
)
REMOTE(∗
1
)
VREF
CS RAMP
RAMP
-SLP
OUT OUT
-C
-D
OUT OUT
-E
-F
COMP
R2A20124AFP/ASP
FB(–)
CS-
DELAY
-1
SS OUT(∗
1
)
DELAY
-2
DELAY
-3
PGND SGND RT SYNC
Note:
∗1.
Only R2A20124AFP
R03DS0031EJ0300 Rev.3.00
Mar 11, 2011
Page 2 of 12
R2A20124AFP/R2A20124ASP
Preliminary
Pin Functions
LQFP-40
Pin No.
1
2
4
5
6
7
9
13
14
17
18
19
20
22
23
—
24
27
29
31
33
34
36
37
38
3, 8,
10 to 12,
15, 16,
21, 25,
26, 28,
30, 32,
35, 39,
40
SOP-20
Pin No.
8
9
10
—
—
11
12
13
14
15
16
17
18
—
—
19
20
1
2
3
4
—
5
6
7
—
Pin Name
DELAY-1
DELAY-2
DELAY-3
SEC-CONT
REMOTE
VREF
VCC
OUT-F
OUT-E
OUT-D
OUT-C
OUT-B
OUT-A
PGND
SGND
GND
RT
SYNC
RAMP-SLP
RAMP
CS
CS-OUT
COMP
FB(–)
SS
N.C.
Input/Output
Input/Output
Input/Output
Input/Output
Input
Input
Output
Input
Output
Output
Output
Output
Output
Output
—
—
—
Input/Output
Input/Output
Input/Output
Input
Input
Output
Output
Input
Output
—
Pin Function
Delay time adjustor for the full-bridge control signal (OUT-A and B)
Delay time adjustor for the full-bridge control signal (OUT-C and D)
Delay time adjustor for the secondary control signal (OUT-E and F)
Synchronous rectification on/off control
Remote on/off control
5 V/20 mA output
IC power supply input
Secondary control signal
Secondary control signal
Full-bridge control signal
Full-bridge control signal
Full-bridge control signal
Full-bridge control signal
Ground level for the output signal
Ground level for the small signal
Ground
Timing resistor for the oscillator
Synchronization I/O for the oscillator
Ramp sloping adjustor
Ramp waveform set
Current sense signal input for OCP
Current sense information amplifier output
Error amplifier output
Error amplifier negative input
Timing capacitor for soft start
Open
R03DS0031EJ0300 Rev.3.00
Mar 11, 2011
Page 4 of 12
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