BD8621EFV-E2 [ROHM]
FET Controller Type 3ch System Power Supply ICs; FET控制器类型3通道系统电源IC
| 型号： | BD8621EFV-E2 |
| 厂家： | 
ROHM |
| 描述： | FET Controller Type 3ch System Power Supply ICs |
| 文件： | 总15页 (文件大小：451K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
System Power Supply for TV Series
FET Controller Type
3ch System Power Supply ICs
BD8621EFV
No.09034EAT03
●Description
BD8621EFV has realized the high performance and reliability required as a power supply for thin-screen TV.
With built-in FET 1ch current mode control, the DC/DC Converter series has the advantage of high-speed load response
and wide phase margin.
Due to the high-speed load response, it is most suitable for TV-purpose processors with increasingly high performance, and
due to the wide phase margin it leaves a good margin for board pattern & constant setting and so facilitates its application
design.
As a high-reliability design, it has various built-in protection circuits (overcurrent protection, output voltage abnormal
protection, thermal protection, and off-latch function at the time of abnormality etc.), therefore as an advantage it does not
easily damage in every possible abnormal condition such as all-pin short circuit test etc. and hence most suitable for
thin-screen TV which requires the high reliability.
●Features
1) 3A output current
2) Low RDS(ON) internal switches (PchMOS:75mΩ，NchMOS:55mΩ)
3) ±1% reference voltage accuracy
4) Programmable frequency : 250kHz-1MHz
5) (Frequency in programmable by adjusting RT resistance or synchronizing with SYNCLK terminal.)
6) Terminal RT OPEN/SHORT detecting function
7) Over current protection function
8) Output over voltage/low voltage protection function (over : FB > VREF +60mV , low : FB < VREF -60mV)
9) Timer off latch function in abnormal circumstances
10) Thermal shutdown function
11) Under voltage protection
12) Soft start/start delay circuit
13) Soft start time out function
14) Protecting BUS function with terminal PDET
15) HTSSOP-B20 package
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.05 - Rev.A
1/14
Technical Note
BD8621EFV
●Electrical characteristics
(Unless otherwise noted Ta=25℃, VIN=3.3V, GND=0V)
Specification value
Parameter
Symbol
UNIT
Condition
MIN
-
-
TYP
220
0
MAX
350
1
VIN supply current (operating)
VIN supply current (standby)
Reference voltage (VREF)
IQ_active
IQ_stby
VREF
μA
μA
V
VFB = 0.83V, VFC = 1V
VEN = 0V
0.792
0.8
60
0.808
mV
Monitoring FB
terminal
Output rise detection voltage
VOVP
30
90
-60
mV
Monitoring FB
terminal
Output decrease detection voltage VLVP
-90
-30
Terminal PDET output current
Oscillation frequency
Pch FET ON resistance
Nch FET ON resistance
UVLO voltage
IPDET
fOSC
RPFET
RNFET
VUVLO
ILSW
VENH
VENL
IFCSI
0.4
500
-
-
-
mA
kHz
mΩ
mΩ
V
μA
V
V
μA
μA
μA
kΩ
VPDET< 0.3V
RRT= 220kΩ
ISW = 1A
550
75
55
2.50
0
600
110
90
2.65
1
-
I
SW = 1A
2.35
-
1.1
-
10
-
2
SW leak current
VEN= 0V, VIN = 5.5V
EN terminal H threshold voltage
EN terminal L threshold voltage
FC sink current
FC source current
SS/DELAY terminal source current ISSSO
Terminal PDET pull-up resistor RPDET
-
-
-
0.4
-
-10
6
20
-20
4
IFCSO
100
170
250
VFB :FB terminal voltage, VEN :EN terminal voltage, VFC :FC terminal voltage, VPDET: PDET terminal voltage
Current capability should not exceed Pd.
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2009.05 - Rev.A
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© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
●Block Diagram
Fig1 Block diagram
●Pin Description
No.
1
Symbol
SGND
FB
Description
Signal GND terminal
Explanation
Small signal system GND
Output voltage detection
2
Feed back terminal
3
PDET
SW
Off latch signal output
Protecting BUS communication terminal
4
Output terminal
Switching output
5
SW
6
PGND
PGND
PGND
SW
7
Power GND terminal
Output terminal
GND for power MOSFET
Power Mos output
8
9
10
11
12
13
14
SW
VIN
VIN
Power supply input terminal
Internal Regulator
Power supply input. The decoupling is done to PGND
VIN
VIN
Synchronizable switching output terminal frequency with
external clock
15
REG
16
17
EN
Enable input
ON/OFF control for device operation
SGND short in the set.
TEST
Terminal for test
Soft start adjustment capacity connection
terminal
The soft start time is adjusted with the connected
capacitor
18 SS/DELAY
19
20
FC
RT
Error amplifier output
Error amplifier phase compensation point
Frequency adjustment resistance connection The switching frequency is set by the connected
terminal resistance
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2009.05 - Rev.A
3/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
●Pin equivalence circuit diagram
No.
Symbol
Explanation
Terminal equivalent circuit diagram
1
SGND
GND (connected 0V)
VIN
2
FB
Output voltage detection terminal
2
SGND
3
PDET
Protecting BUS I/O terminal
VIN
4
5
4,5,9,10
SW
Output terminal
9
10
PGND
Power GND
(Same voltage as SGND)
6,7,8
PGND
VIN
11,12,13,14
Power supply input terminal
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2009.05 - Rev.A
4/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
No.
Symbol
Explanation
Terminal equivalent circuit diagram
15
REG
Internal Regulator output voltage
16
EN
Enable terminal
17
TEST
Using at test mode
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2009.05 - Rev.A
5/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
No.
Symbol
Explanation
Terminal equivalent circuit diagram
SS
/DELAY
18
Soft start time adjustment terminal
Error amplifier compensation
terminal
19
FC
Oscillator frequency adjustment
terminal
20
RT
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2009.05 - Rev.A
6/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
●Operation description
Enable control
The device can be controlled ON/OFF by EN terminal (16 pin) voltage.
An internal circuit starts when VEN reaches 1.1V.
EN terminal voltage
SS terminal voltage
Output setting voltage
Fig.2 ON/OFF transition wave form in EN controlling
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2009.05 - Rev.A
7/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
Soft start time set function
As for BD8621EFV, output can do soft start without overshoot by charging soft start capacity (CSS) connected between SS
and SGND terminal.
Also, soft start time (tss) can be set by setting soft start capacity (CSS) arbitrarily.
OSC oscillation frequency setting function
The output oscillation frequency can be set by connecting resistance between terminal RT (20 pins) and SGND
(range = 250kHz - 1MHz)
The relation between RT terminal resistance and the oscillation frequency follows Fig.3.
1000
10
10
100
1000
10000
RT terminal resistanceꢀ[kΩ]
Fig.3 RT resistance-oscillation frequency
Switching frequency synchronization
An internal transmitter of BD8621EFV can be synchronized with the external clock signal connected with the terminal
SYNCLK (15 pins).
The frequency of external clock can be set within the range of 250kHz-1MHz. In this case, please set the RT resistance that
may become about -20% value of the external clock frequency.
* Be short-circuited SYNCLK terminal to SGND when a frequency synchronous function is not used.
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2009.05 - Rev.A
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© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
●Protection function
Protection circuit is effective for destruction prevention due to accident so that avoid using under continuous protection
operation.
Low voltage protection function (LVP)
The voltage of the terminal FB (2 pins) is compared with internal reference voltage VREF.
If FB terminal voltage falls below VLVP(= VREF -60mV) and the state continues for 500us, output changes to low voltage and
the state is fixed. In that case , PDET (3pin) output changes to L.
Table 1 output low voltage protection function
Low voltage protection Low voltage protection
EN terminal
>VENH
SS terminal
>1.4V(typ)
FB terminal
function
operation
＜VLVP
＞VLVP
ON
Effective
OFF
OFF
OFF
<1.4V(typ)
-
-
-
Invalidity
Invalidity
<VENL
* Low voltage protection function is available when SS terminal voltage becomes more than
1.4V (typ) in the transition to ON control (during soft start).
Over voltage protection function(OVP)
The voltage of the terminal FB is compared with internal reference voltage VREF.
If FB terminal voltage is over Vovp (=VREF +60mV) and the state is continues for 500usec, output changes to low voltage
and the state is fixed.
Table 2 output overvoltage protection function
Over voltage
protection function
Over voltage
protection operation
ON
EN terminal
>VENH
SS terminal
>1.4V(typ)
FB terminal
＞VOVP
＜VOVP
Effective
OFF
OFF
OFF
<1.4V(typ)
-
-
-
Invalidity
Invalidity
<VENL
* Over voltage protection function is available when SS terminal voltage becomes more than
1.4V (typ) in the transition to ON control (during soft start).
VFB
VREF＋60ｍV
FB terminal voltage
VREF
VREF-60ｍV
0
ON
Protection
OFF
LVP
OVP
LVP
HIGH
LOW
PDET terminal
Fig.4 Output voltage error detection range
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.05 - Rev.A
9/14
Technical Note
BD8621EFV
Under voltage lock out protection (UVLO)
As for BD8621EFV, the power-supply voltage decrease detection protection circuit is built in.
It the input voltage decrease below the UVLO voltage (2.5V typ), the device state changes to the standby mode (Moreover,
to prevent the chattering of the output) hysteresis width of 100mV(typ) has been installed in the UVLO cancel voltage.
RT terminal open/short protection function (RTO/RTS)
RT terminal opening/short protection function prevent the clock from abnormal oscillation.
If RT terminal open/short protection function is detected, output voltage changes to low level and is fixed.
Terminal RT opening/short protection function is available if the state continue for 500usec, abnormal detection operates
when the state continues about 500μsec(typ).
Soft start time-out function
If VSS doesn't exceed VSSTH within 64msec (typ) since a soft start began, BD8621EFV controls an off latch.
Vo is fixed in a low level.
Fig.5 Soft start time-out
Thermal shut down function
Thermal shut down circuit (TSD circuit) is built into BD8621EFV. When the temperature of the chip exceeds Tjmax=175, the
DC/DC converter is fixed in a low voltage.
TSD function is aimed to shut down IC from thermal reckless driving under an abnormal state to exceed Tjmax=175.
It aims at neither protection nor the guarantee of the set. Therefore, please do not use this function to protect the set.
Over current protection function
The over current protection function has been achieved by limiting the current that flows on high side MOSFET.
The current is controlled in every one cycle of the switching frequency. When an abnormal state continues for about
500μsec(typ), the output is fixed in a low level.
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2009.05 - Rev.A
10/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
Protecting BUS function with terminal PDET
The terminal PDET (3 pins) monitors whether IC is normal or not. When IC becomes abnormal, the PDET output is reduced
at "L" level with the output voltage fixed “L” level at the same time. Moreover, it is possible to make the output fix in a low
level by compulsorily reducing the terminal PDET at "L" level from the outside.
When two or more BD8621EFV is used in the application, this function prevents the IC from destroying, because one IC
error transmits all other ICs by PDET line in the condition that PDET terminals are connected each other.
Fig.6 Protecting BUS communication
※Please give the terminal PDET as OPEN when you do not use protecting BUS function.
Error detection (off latch) release method
BD8621EFV enters the state of an off latch when the protection function operates.
To release the off latch state, EN terminal voltage should be changed to low level once time.
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2009.05 - Rev.A
11/14
© 2009 ROHM Co., Ltd. All rights reserved.
Technical Note
BD8621EFV
●Each characteristic reference data
VIN = 5V
Io = 3A
VIN = 5V
Vout : 20mV/div
Vout : 100mV/div
Io = 1A/div
1usec/div
Fig.7 Output load response
Fig.8 Output ripple
VIN = 2V/div
VIN = 3.3V
VOUT = 0.5V/div
VIN = 5.0V
SS = 2V/div
10msec/div
VOUT = 1.2V
Fig.9 Efficiency
Fig.10 Soft start
VIN = 5.0V
VOUT = 1.2V
Fig.11 Regulation
0.810
0.808
0.806
0.804
0.802
0.800
0.798
0.796
0.794
0.792
0.790
5.0
4.8
4.5
4.3
4.0
3.8
3.5
3.3
3.0
VIN = 3.3V
VIN = 3.3V
-25
0
25
50
75
100
-25
0
25
50
75
100
AMB IE NT T E MP E RAT URE : T a [℃]
AMB IE NT T E MP E RAT URE : T a [℃]
Fig.12 Reference voltage - Temperature characteristic
Fig.13 SS Charging current - Temperature characteristic
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.05 - Rev.A
12/14
Technical Note
BD8621EFV
600.0
590.0
580.0
570.0
560.0
550.0
540.0
530.0
520.0
510.0
500.0
VIN = 3.3V
Ta = 25℃
-25
0
25
50
75
100
AMB IE NT T E MP E RAT URE : T a [℃]
Fig.14 Switching frequency-power-supply voltage
Fig.15 Switching frequency-temperature characteristic
110.00
100.00
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
VIN = 3.3V
90.00
Ta = 25℃
80.00
70.00
60.00
50.00
40.00
30.00
-25
0
25
50
75
100
2.5
3
3.5
4
4.5
5
5.5
AMB IE NT T E MPE RAT URE : T a [℃]
INP UT VOL T AG E : Vin [V]
Fig.16 PMOS on resistance-power-supply voltage
Fig.17 PMOS on resistance-temperature characteristic
90.00
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
80.00
VIN = 3.3V
70.00
60.00
50.00
40.00
30.00
20.00
10.00
Ta = 25℃
2.5
3
3.5
4
4.5
5
5.5
-25
0
25
50
75
100
INP UT VOL T AG E : Vin [V]
AMB IE NT T E MP E RAT URE : T a [℃]
Fig.18 NMOS on resistance-power-supply voltage
Fig.19 NMOS on resistance-temperature characteristic
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
VIN = 3.3V
Ta = 25℃
VFB = 0.83V
VFC = 1.0V
SW = High
-25
0
25
50
75
100
AMB IE NT T E MP E RAT URE : T a [℃]
Fig.20 Terminal EN H voltage-temperature characteristic
Fig.21 Circuit current-power-supply voltage characteristic
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.05 - Rev.A
13/14
Technical Note
BD8621EFV
●Ordering part number
B
D
8
6
2
1
E
F
V
-
E
2
Part No
Part No.
Package
EFV: HTSSOP-B20
Packaging and forming specification
E2: Embossed tape and reel
HTSSOP-B20
<Dimension>
<Tape and Reel information>
Tape
Embossed carrier tape
6.5 0.1
Quantity
2500pcs
20
11
Direction
of feed
E2
(The direction is the 1pin of product is at the upper left when you hold
reel on the left hand and you pull out the tape on the right hand)
1
10
+0.05
−0.03
0.325
0.17
S
0.08
S
0.65
0.2 −+00..0045
Direction of feed
1pin
Reel
（Unit:mm)
※When you order , please order in times the amount of package quantity.
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.05 - Rev.A
14/14
Notice
N o t e s
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consent of ROHM Co.,Ltd.
The content specified herein is subject to change for improvement without notice.
The content specified herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specifications,
which can be obtained from ROHM upon request.
Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.
Great care was taken in ensuring the accuracy of the information specified in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.
The technical information specified herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.
The Products specified in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, office-automation equipment, commu-
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Please be sure to implement in your equipment using the Products safety measures to guard
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R0039
A
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