Datasheet.kr   

AN020 데이터시트 PDF




AIC에서 제조한 전자 부품 AN020은 전자 산업 및 응용 분야에서
광범위하게 사용되는 반도체 소자입니다.


PDF 형식의 AN020 자료 제공

부품번호 AN020 기능
기능 The Power Management of PDA
제조업체 AIC
로고 AIC 로고


AN020 데이터시트 를 다운로드하여 반도체의 전기적 특성과 매개변수에 대해 알아보세요.




전체 7 페이지수

미리보기를 사용할 수 없습니다

AN020 데이터시트, 핀배열, 회로
AN020
The Power Management of PDA—The Application
of SEPIC Circuit
Introduction
The PDA (Personal Digital Assistant) appeals to an
increasing number of users because of its multifunction
such as: Wireless Communication, Organizer, Mobile
Phone, Handwriting Recognition, Web Access, Flash
Memory, and Data/fax Modem. The users can choose
their favorites among various brands according to their
individual requirement. And the efficiency and the
duration of the battery used in the products are critical
to the users.
From the designers’ point of view, the circuit for power
management becomes obviously substantial. Here
goes the block diagram of circuit in PDA.
Referred to Fig.1, it is easily seen that there are two
possible combinations for input.
One way is to combine 2 Ni-MH cells and a 6V adapter.
The combination causes the input voltage ranging from
1.8V to 2.6V. The other way is to put a Li-Ion battery
and an adapter together. That results in a range from
2.4V to 4.3V for the input voltage. To have a regulated
3.3V input voltage for the controller, the voltage
obtained from battery needs another treatment. The
conventional method is to boost the battery voltage
and then reduce it to what we expect. In this manner,
regulated voltages are obtained from the battery
steadily, regardless of the original level of the battery.
described above. For example, there would be an
increase of the number of elements and space, higher
cost, reduced reliability, and low efficiency of power
transfer. This article introduces a better approach to
achieve a regulated voltage. The benefits of the
simplified circuit with low cost and high efficiency may
result from this approach.
Operation Principle
A. The Description of the Circuit
Referred to Fig. 2, the SEPIC (Single End Primary
Inductor Circuit) meets the requirement for the
output voltage to tolerate any levels of voltage from
input. You might have heard of ”SEPIC”, yet the
corresponding operation theory, design guide, and
application are not often employed in the literature.
We provide insight of the circuit for your design.
As shown in Fig.2, L1 and L2 are chokes. They can
be coupled or uncoupled. C1 and C2 are aluminum
electrolytic capacitors. M1 is MOSFET and D1 is the
power diode. When M1 turns on, D1 is off and VIN
and C1 provide energy to L1, L2, respectively. In
turn, as M1 turns off, D1 is on. L1 charges C1. L1
and L2 provide electric energy to C2 and load from
magnetic energy stored before. In steady state, the
average voltage of L1 and L2 is zero and that of C1
is VIN.
Nevertheless, there are some defects in the method
April, 2001
1




AN020 pdf, 반도체, 판매, 대치품
AN020
M1-ON
VGS 0
IL1 0 VIN
IL2 0 VIN
VC1 VIN
0
VD1 0
-(VIN+VOUT)
M1-OFF
-VO
-VO
Fig.5 (b) The Plots of Voltages
In steady state, the characteristic of inductor is the
voltage-second balance. Therefore, we can obtain
the relationship between VIN and VOUT in (1). If
we neglect the power loss in the converting circuit,
PINPUT equals POUTPUT. And the relationship of
current between input and output is shown in (3),
where D is the duty cycle.
VIN × D × TS = VOUT × (1 D)× TS …..…….… (1)
VOUT
VIN
=
D
1D
……………………..…………(2)
IIN
IOUT
=
D
1D
……………………….………….(3)
Design Guide
From the description above, here is a typical design
example.
In MP3 or PDA, the battery is the power source to the
DC/DC converter. The voltage fluctuates due to the
change of battery capacity. To obtain regulated voltage
from battery source regardless the level of the voltage,
the SEPIC circuit is preferred.
There are some specifications in this design example:
The range of input voltage: 2.9V~4.5V
The desired output voltage: 3.3V
The maximum current: IOUT=500mA
Step 1: Selection of L1 and L2.
AIC1630A, one of products for power management
from AIC, is the switching controller whose switching
frequency is from 90kHz to 150KHz.
Ts=1/FS.MIN=1/90k=11.1µS,

VOUT
VIN
MIN
=
DMAX
1 DMAX
,
3.3
2.9
=
DMAX
1DMAX
,
DMAX=0.53……the maximum duty ratio
IOUT-BOUNDARY=IOUT-MAX=0.5A,
( )L1
>
VOUT × TS × 1 D
2 × IOUTBOUNDARY
L1>17.2µH
Let L1 be 25µH.
IIN
=
PIN
VIN
=
POUT
EFF. × VIN
=
3.3 × 0.5
0.8 × 2.9
= 0.71A
Step 2: Selection of C1
4

4페이지










AN020 전자부품, 판매, 대치품
AN020
Summary
Based on the calculation and description above, the
SEPIC can be accurately designed. It is recommended
especially in the applications where the battery is the
power source in the appliances or the regulated
voltage is demanded from the power source regardless
the level of the voltage.
Although the efficiency of SEPIC circuit is lower than
BUCK converter or BOOST converter, it beats the
conventional method, that is, boosting the source
voltage first and reducing it afterwards. For the low
power-consumption portable appliances, SEPIC is a
good option with benefits of simple circuit and low
ripple current.
We sincerely hope that this circuit could be of some
help to engineers in related field. Other topics, e.g. the
power management of portable appliances, the circuit
combined to the charger, the boost mode circuit and
some problems encountered in the design process, will
be presented in the near future.
Reference:
[1]. AIC1630A Datasheet, Analog Integrations
Corporation 2000.
7

7페이지


구       성 총 7 페이지수
다운로드[ AN020.PDF 데이터시트 ]

당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는

포괄적인 데이터시트를 제공합니다.


구매 문의
일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한
광범위한 전력 반도체를 판매합니다.

전력 반도체 전문업체

상호 : 아이지 인터내셔날

사이트 방문 :     [ 홈페이지 ]     [ 블로그 1 ]     [ 블로그 2 ]



관련 데이터시트

부품번호상세설명 및 기능제조사
AN020

The Power Management of PDA

AIC
AIC
AN021

A Handy Method to Obtain Satisfactory Response of Buck Converter

AIC
AIC

DataSheet.kr       |      2020   |     연락처      |     링크모음      |      검색     |      사이트맵