BP5021 [ROHM]
DC-DC Regulated Power Supply Module, 1 Output, Hybrid, SIP-9/8;型号: | BP5021 |
厂家: | ROHM |
描述: | DC-DC Regulated Power Supply Module, 1 Output, Hybrid, SIP-9/8 |
文件: | 总9页 (文件大小:147K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Regulator ICs
DC / DC converter
BP5020 / BP5021 / BP5022
The BP5020, BP5021, and BP5022 are DC / DC converter units that use a pulse width modulation (PWM) system. They
containcontrolcircuits, switchingdevices, rectifiers, andcoils, andoperatebyonlyconnectinganI / Osmoothingcapac-
itor. With a high efficiency of power conversion, the ICs are available in stand-alone 9-pin SIP packages with no heat
sink required. They can be applied to various purposes by fine-adjusting the output control and output voltage. With a
wide range of input voltage, the ICs are best suited for obtaining a stable local power source from a main power supply
with a large voltage variation.
FApplications
Power supplies for copiers, personal computers, word processors, measuring instruments, vending machines, security
devices, registers, industrial equipment, and maintenance tools
FFeatures
1) Wide range of input voltage.
4) Small number of external components required.
5) Heat sink unnecessary.
2) High power conversion efficiency.
3) Applicable to various purposes by fine-adjusting the
output control and output voltage with external cir-
cuits.
6) Compact SIP 9-pin package.
FBlock diagram
312
Regulator ICs
BP5020 / BP5021 / BP5022
FList of the BP502-series
FAbsolute maximum ratings (Ta = 25_C)
313
Regulator ICs
BP5020 / BP5021 / BP5022
FElectrical characteristics
BP5020 (unless otherwise noted, VI = 15V, IO = 0.5A, SW = 1, Ta = 25_C)
BP5021 (unless otherwise noted, VI = 15V, IO = 0.25A, SW = 1, Ta = 25_C)
BP5022 (unless otherwise noted, VI = 20V, IO = 0.25A, SW = 1, Ta = 25_C)
314
Regulator ICs
BP5020 / BP5021 / BP5022
FMeasurement circuit
315
Regulator ICs
BP5020 / BP5021 / BP5022
FCircuit operation
The switching transistor in the hybrid IC can be forcedly
turned off by putting pin 4 to the open state (high imped-
ance). The output voltage can be fine-adjusted be con-
necting a capacitor to pin 6, which is connected to the
output voltage sensing circuit.
FApplication example
Application 1: DC / DC converter with a protection circuit
A resistor to secure the rise of output at power on. The
resistance to be selected depends on the input voltage.
This is a standard application. Because the control cur-
rent fluctuates with variations in circuits and compo-
nents, set the control current by adding a sufficient mar-
gin to the normal current level.
Application 2: Output ON / OFF control
C1isaslow-startcapacitorformitigatingtheexcessiverushcurrentthatflowsintothehybridICwhentheswitchisturned
on.
316
Regulator ICs
BP5020 / BP5021 / BP5022
Application 3: Output voltage fine adjustment
i) When reducing the output voltage
ii) When increasing the output voltage
VR value setting equations (the output voltage after adjustment is denoted as VO)
i) When reducing the output voltage
BP5020 / BP5021 R = (VO * 1.281) / (0.0278 * 0.00556VO) (kΩ)
BP5022
ii)
R = (VO * 1.281) / (0.1196 * 0.01VO) (kΩ)
When increasing the output voltage
BP5020 / BP5021 R = 11160 / (48.4VO * 242) (kΩ)
BP5022
R = 1200 / (9.368VO * 112) (kΩ)
To make full use of the ability of the hybrid IC, we recom-
mend the output voltage be adjustment within ±20% of
the output voltage rating. When the output voltage is in-
creased by 20%, for instance, the minimum input voltage
is also increased by 20 %.
(Example: When the output voltage is changed from 5V
to 6V in the BP5020, the minimum input voltage is
changed from 8V to 9.6V.)
Application 4: Slow start
Theslowstartcircuitmitigatesthepulseloadontheinter-
nal switching transistor when input voltage is applied,
and rises the output voltage gradually by starting the
switching operation slowly.
This application is useful for preventing the malfunction
of an external protection circuit due to a rush current, and
can serve as a countermeasure against the operation
outside the safe operation range.
C1isaslow-startcapacitorformitigatingtheexcessiverushcurrentthatflowsintothehybridICwhentheswitchisturned
on.
317
Regulator ICs
BP5020 / BP5021 / BP5022
FPin noise voltage
cuit of Fig. 10 is shown in Fig. 9.
318
Regulator ICs
BP5020 / BP5021 / BP5022
FOperation notes
(1) The output current should be reduced according to
an increase in the input voltage or ambient temperature.
Use the IC within the derating curve range.
(2) Pins 5 and 7 are not used.
The safe operation range of the IC is determined by the
safe operation range of the internal switching transistor.
The amount of rush current depends on the output im-
pedance of the input power supply and capacitors con-
nected to the IC outputs. The pulse load on the internal
switching transistor at the start of operation can be re-
duced by using the protection circuit of application 1 or
the slow start circuit of application 4.
(3) No circuit is installed in the IC to protect against ex-
cessive output currents. Take physical safety measures
such as fusing if short-circuit loading is probable.
(4) A large rush current may flow in the IC when the in-
put voltage is applied or the output ON / OFF is con-
trolled with pin 4 without a capacitor such as C1 in ap-
plication2. Complywiththesafeoperationrangesshown
in Figs. 13, 16, and 19.
FElectrical characteristic curves
For the BP5020
For the BP5021
319
Regulator ICs
BP5020 / BP5021 / BP5022
For the BP5022
FExternal dimensions (Units: mm)
320
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