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부품번호 | UCC2941-5 기능 |
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기능 | (UCCx941-x) 1V Synchronous Boost Converter | ||
제조업체 | Unitrode | ||
로고 | |||
www.DataSheet4U.com
1V Synchronous Boost Converter
application
INFO
available
UCC2941-3/-5/-ADJ
UCC3941-3/-5/-ADJ
FEATURES
• 1V Input Voltage Operation Startup
Guaranteed Under Full Load on Main
Output With Operation Down to 0.4V
• Input Voltage Range of 1V to VOUT +
0.5V
• 500mW Output Power at Battery
Voltages as Low as 0.8V
• Secondary 9V Supply From a Single
Inductor
• Adjustable Output Power Limit Control
• Output Fully Disconnected in
Shutdown
• Adaptive Current Mode Control for
Optimum Efficiency
• 8µA Shutdown Supply Current
DESCRIPTION
The UCC3941 family of low input voltage single inductor boost converters
are optimized to operate from a single or dual alkaline cell, and step up to
a 3.3V, 5V, or an adjustable output at 500mW. The UCC3941 family also
provides an auxiliary 9V 100mW output, primarily for the gate drive supply,
which can be used for applications requiring an auxiliary output such as a
5V supply by linear regulating. The primary output will start up under full
load at input voltages typically as low as 0.8V, with a guaranteed maximum
of 1V, and will operate down to 0.4V once the converter is operating, maxi-
mizing battery utilization.
Demanding applications such as Pagers and PDA’s require high efficiency
from several milli-watts to several hundred milli-watts, and the UCC3941
family accommodates these applications with >80% typical efficiencies
over the wide range of operation. The high efficiency at low output current
is achieved by optimizing switching and conduction losses along with low
quiescent current. At higher output current the 0.25Ω switch, and 0.4Ω syn-
chronous rectifier, along with continuous mode conduction, provide high ef-
ficiency. The wide input voltage range on the UCC3941 family can
accommodate other power sources such as NiCd and NiMH.
Other features include maximum power control and shutdown control.
Packages available are the 8-pin SOIC (D) and 8-pin DIP (N or J).
SIMPLIFIED BLOCK DIAGRAM AND APPLICATION CIRCUIT
10µF
22µH
+ 0.8V TO VOUT +0.5V
8V
VGD
2
10µF
VIN
3
STARTUP
CIRCUITRY
SW
8
0.4Ω
0.25Ω
OPEN=SD
MODULATOR CONTROL CIRCUIT
SYNCHRONOUS RECTIFICATION CIRCUITRY
ANTI-CROSS CONDUCTION
STARTUP
MULTIPLEXING LOGIC
MAXIMUM INPUT POWER CONTROL
ADAPTIVE CURRENT CONTROL
SD
4
UCC3941-ADJ
–
+ 1.25V
*FOR UCC3941-ADJ ONLY:
PIN 7 = SGND & PGND, PIN 6 = OUTPUT SENSE FEEDBACK, FB.
SLUS242 - JULY 1999
UCC3941-3 = 3.3V
UCC3941-5 = 5.0V
UCC3941-ADJ = 1.30V TO 6V
VOUT
1
100µF
PLIM
5
*SGND/FB
6
PGND
7
UDG-98147
UCC2941-3/-5/-ADJ
UCC3941-3/-5/-ADJ
APPLICATION INFORMATION
A detailed block diagram of the UCC3941 is shown in
Fig. 1. Unique control circuitry provides high efficiency
power conversion for both light and heavy loads by tran-
sitioning between discontinuous and continuous conduc-
tion based on load conditions. Fig. 2 depicts converter
waveforms for the application circuit shown in Fig. 3. A
single 22µH inductor provides the energy pulses required
for a highly efficient 3.3V converter at up to 500mW out-
put power.
VIN
3
ANTI-RINGING
SWITCH
SW
8
VGD
VGD 2
200kHz
STARTUP
OSCILATOR
AND CONTROL
+
5V –
PLIM 5
1.4A
5Ω MAX
50mV
MAXIMUM
CURRENT
LIMIT
+
–
SD
SD 4
50mV
VIN
VIN
THERMAL
SHUTDOWN
FROM
SD
VGD
VGD ZERO
DETECT
+
–
VOUT ZERO
DETECT
–
+
1.7µS
OFF TIME
CONTROLLER
VGD
RECTIFIER
CONTROL
FROM SD
CLK
DQ
L1
VSAT
ON TIME
CONTROLLER
TON=
11µSEC
VIN
QR
SD
RQ
SD
BOOST
LATCH
* 3.3V FOR UCC3941-3
5.0V FOR UCC3941-5
1.25V FOR UCC3941-ADJ
** 8.7V FOR UCC3941-3
9.6V FOR UCC3941-5/-ADJ
*** 7.7V FOR UCC3941-3
8.8V FOR UCC3941-5/-ADJ
–
+*
– VGD
+ **
– VGD
+ ***
1 VOUT
FB FOR
6 UCC3941-ADJ
ONLY
6 SGND FOR
UCC3941-3/-5
7 PGND
Note: Switches are shown in the logic low state.
Figure 1. 1V Synchronous boost.
UDG-98146
4
4페이지 UCC2941-3/-5/-ADJ
UCC3941-3/-5/-ADJ
APPLICATION INFORMATION (cont.)
1.0V input.
Inductor Section
An inductor value of 22µH will work well in most applica-
tions, but values between 10µH and 100µH are also ac-
ceptable. Lower value inductors typically offer lower ESR
and smaller physical size. Due to the nature of the
“bang-bang” controllers, larger inductor values will typi-
cally result in larger overall voltage ripple, because once
the output voltage level is satisfied the converter goes
discontinuous, resulting in the residual energy of inductor
causing overshoot.
It is recommended to keep the ESR of the inductor below
0.15Ω for 500mW applications. A Coilcraft DT3316P-223
surface mount inductor is one choice since it has a cur-
rent rating of 1.5A and an ESR of 84mΩ. Other choices
Table 1. Inductor Suppliers
MANUFACTURER
Coilcraft
Cary, Illinois
Tel: 708-639-2361
Fax: 708-639-1469
Coiltronics
Boca Raton, Florida
Tel: 407-241-7876
PART NUMBERS
DT Series
CTX Series
for surface mount inductors are shown in Table 1.
Output Capacitor Selection
Once the inductor value is selected the capacitor value
will determine the ripple of the converter. The worst case
peak to peak ripple of a cycle is determined by two com-
ponents, one is due to the charge storage characteristic,
and the other is the ESR of the capacitor. The worst case
ripple occurs when the inductor is operating at maximum
current and is expressed as follows:
∆V
=
(ICL )2 • L
2 • C • (VO −VI )
+ ICL
• CESR
where
ICL = the peak inductor current
ICL
=
Power Limit
VIN
∆V = output ripple
VO = output voltage
VI = input voltage
CESR = ESR of the output capacitor
A Sanyo OS-CON series surface mount capacitor
(10SN100M) is one recommendation. This part has an
ESR rating of 90mΩ at 100µF. Other potential capacitor
sources are shown in Table 2.
Table 2. Capacitor Suppliers
MANUFACTURER
Sanyo Video
Components
San Diego, California
Tel: 619-661-6322
Fax: 619-661-1055
AVX
Sanford, Maine
Tel: 207-282-5111
Fax: 207-283-1941
Sprague
Concord, New Hampshire
Tel: 603-224-1961
PART NUMBER
OS-CON Series
TPS Series
695D Series
Input Capacitor Selection
Since the UCC3941 family does not require a large de-
coupling capacitor on the input voltage to operate prop-
erly, a 10µF capacitor is sufficient for most applications.
Optimum efficiency will occur when the capacitor value is
large enough to decouple the source impedance. This
usually occurs for capacitor values in excess of 100µF.
7
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부품번호 | 상세설명 및 기능 | 제조사 |
UCC2941-3 | (UCCx941-x) 1V Synchronous Boost Converter | Unitrode |
UCC2941-3 | 1-V Synchronous Boost Converter (Rev. B) | Texas Instruments |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |