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UCC3941-3 の電気的特性と機能

UCC3941-3のメーカーはUnitrodeです、この部品の機能は「(UCCx941-x) 1V Synchronous Boost Converter」です。


製品の詳細 ( Datasheet PDF )

部品番号 UCC3941-3
部品説明 (UCCx941-x) 1V Synchronous Boost Converter
メーカ Unitrode
ロゴ Unitrode ロゴ 




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UCC3941-3 Datasheet, UCC3941-3 PDF,ピン配置, 機能
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 0.25switch, and 0.4syn-
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
0.4
0.25
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

1 Page





UCC3941-3 pdf, ピン配列
UCC2941-3/-5/-ADJ
UCC3941-3/-5/-ADJ
ELECTRICAL CHARACTERISTICS: Unless otherwise specified, for UCC3941, TA = 0°C to 70°C; for UCC2941, TA = –40°C
to 85°C; VIN = 1.25V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN TYP MAX UNITS
Inductor Charging Section
Charge Switch RDS(on)
N and D Package, I = 200mA
0.25 0.4
Current Limit Delay
(Note 1)
50 ns
Synchronous Rectifier Section
Rectifier RDS(on)
N and D Package, I = 200mA, UCC3941-ADJ VOUT = 3.3V
and UCC3941–3
0.35 0.6
N and D Package, I = 200mA, UCC3941-5
0.5 0.8
Shutdown Section
Shutdown Bias Current
–10 –7
µA
Note 1: Performance from application circuit shown in Figures 3 - 5 guaranteed by design and alternate testing methods, but not
100% tested as shown in production.
Note 2: For the UCC3941-3, VOUT = 3.47V and VGD = 9.3V. For the UCC3941-5, VOUT = 5.25V, VGD = 9.3V. For the UCC3941-
ADJ, FB = 1.315V, VGD = 9.3V.
PIN DESCRIPTIONS
FB: Feedback control pin used in the UCC3941-ADJ
version only. The internal reference for this comparator is
1.25V and external resistors provide the gain to the
output voltage.
PGND: Power ground of the IC. The inductor charging
current flows through this pin. For the UCC3941-ADJ
signal ground and power ground lines are tied to a
common pin.
PLIM: This pin is programmed to set the maximum input
power for the converter. For example a 1A current limit at
1V would have a 333mA limit at 3V input keeping the
input power constant at 1W. The peak current at VIN =
1V is programmed to 1.5A (1.5W) when this pin is
grounded. The power limit is given by:
11.8 n
PL(W) = RPL + 6.7 +VIN (0 . 26)
where RPL is equal to the external resistor from the PLIM
pin to ground and n is the expected efficiency of the
converter. The peak current limit is given by:
11.8 n
( )IPK
( A)
=
VIN
RPL + 6.7
+ 0 .26
Constant power gives several advantages over constant
current such as lower output ripple.
SD: When this pin is open, the built in 7µA current source
pulls up on the pin and programs the IC to go into
shutdown mode. This pin requires an open circuit for
shutdown and will not operate correctly when driven to a
logic level high with TTL or CMOS logic. When this pin is
connected to ground, (either directly or with a transistor)
the IC is enabled and both output voltages will regulate.
SGND: Signal ground of the IC. For the UCC3941-ADJ
signal ground and power ground lines are tied to a
common pin.
SW: An inductor is connected between this node and
VIN. The VGD (Gate Drive Supply) flyback diode is also
connected to this pin. When servicing the 3.3V supply,
this pin will go low charging the inductor, then shut off,
dumping the energy through the synchronous rectifier to
the output. When servicing the VGD supply, the internal
synchronous rectifier stays off, and the energy is diverted
to VGD through the flyback diode. During discontinuous
portions of the inductor current a MOSFET resistively
connects VIN to SW damping excess circulating energy
to eliminate undesired high frequency ringing.
VGD: The VGD pin which is coarsely regulated around
9V and is primarily used for the gate drive supply for the
power switches in the IC. This pin can be loaded with up
to 10mA as long as it does not present a load at voltages
below 2V. This ensures proper startup of the IC. The
VGD supply can go as low as 7.5V without interfering
with the servicing of the 3.3V output. Below 7.5V, VGD
will have the highest priority, although practically the
voltage should not decay to that level if the output
capacitor is sized properly.
VIN: Input voltage to supply the IC during startup. After
the output is running the IC draws power from VOUT or
VGD.
VOUT: Main output voltage (3.3V, 5V or adjustable)
which has highest priority in the multiplexing scheme, as
long as VGD is above the critical level of 7.5V. Loads
over 150mA are achievable at 1V input voltage. This
output will startup with 1V input at full load.
3


3Pages


UCC3941-3 電子部品, 半導体
UCC2941-3/-5/-ADJ
UCC3941-3/-5/-ADJ
APPLICATION INFORMATION (cont.)
Programming the Power Limit
The UCC3941 incorporates an adaptive power limit con-
trol which modifies the converter current limit as a func-
tion of input voltage. In order to program the function, the
user simply determines the output power requirements
and makes an initial converter efficiency estimate. The
programming resistor is chosen by:
11.8 n
RPL = POUT – 0.26 n VBAT – 6 .7
Where n is the initial efficiency estimate. For 500mW of
output power, with a 1.0V input, and an efficiency esti-
mate of 0.75:
11.8 (0 .75)
RPL = 0 .5 – 0 .26 (0 .75)(1.0) – 6 .7 = 22
For decreasing values of RPL, the power limit increases.
Therefore, to insure that the converter can supply
500mW of output power, a power limiting resistor of less
than 22must be chosen.
PL
=VBAT
IL
11.8
= 22 + 6.7
+1.0 (0 .26) = 0.67W
This power limiting setting will support 0.5W of output
power. It should be noted that the power limit equation
contains an approximation which results in slightly less
actual input power than the equation predicts. This dis-
crepancy results from the fact that the average current
delivered to the load will be less than the peak current
set by the power limit function due to current ripple. How-
ever, if the ripple component of the current is kept low,
the power limit equation can be used as an adequate es-
timate of input power. Furthermore, since an initial effi-
ciency estimate was required, sufficient margin can be
built into this estimate to insure proper converter opera-
tion. The 6.2external power limit resister in Fig. 3-5 will
result in approximately 700mW of power capability with a
10µF
MMSZ5240BT1
DT3316P-223
22µH
+1V TO 5.5V
38
VIN
8V
2 VGD
SW
5.0V AT 500mW
VOUT 1
10SN100M
10µF
UCC3941-5
100µF
4 SD
OPEN =
SD
PLIM 5
ADJ 6
PGND 7
RPL
6.2
WCR0805-6R207
UDG-98159
Figure 4. Dual output synchronous boost 5V version.
10µF
MMSZ5240BT1
DT3316P-223
22µH
+1V TO 3.5V
10µF
MMSZ5240BT1
DT3316P-223
22µH
+1V TO VOUT + 0.5V
38
VIN SW
3.3V AT 500mW
8V 2 VGD
VOUT 1
10SN100M
10µF
UCC3941-3
100µF
4 SD
OPEN =
SD
PLIM 5
SGND 6
PGND 7
RPL
6.2
WCR0805-6R207
UDG-98163
Figure 3. Dual output synchronous boost 3.3V
version.
3
VIN
8
SW
VOUT=1.25(1+
R1
R2
)
3.3V AT 500mW
10V 2 VGD
VOUT 1
10SN100M
10µF
UCC3941-3
100µF
R1
4 SD
OPEN =
SD
SGND 6
PLIM 5
PGND 7
RPL
6.2
WCR0805-6R207
R2
UDG-98164
Figure 5. Dual output synchronous boost ADJ
version.
6

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共有リンク

Link :


部品番号部品説明メーカ
UCC3941-3

(UCCx941-x) 1V Synchronous Boost Converter

Unitrode
Unitrode
UCC3941-3

1-V Synchronous Boost Converter (Rev. B)

Texas Instruments
Texas Instruments
UCC3941-5

(UCCx941-x) 1V Synchronous Boost Converter

Unitrode
Unitrode
UCC3941-5

1-V Synchronous Boost Converter (Rev. B)

Texas Instruments
Texas Instruments


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