application
INFO
UCC19411/2/3
UCC29411/2/3
UCC39411/2/3
PRELIMINARY
available
Low Power Synchronous Boost Converter
FEATURES
DESCRIPTION
• 1V Input Voltage Operation Start-up
Guaranteed under FULL Load on
Main Output, and Operation Down to
0.5V
The UCC39411 family of low input voltage, single inductor boost
converters is optimized to operate from a single or dual alkaline cell, and
steps up to a 3.3V, 5V, or adjustable output at 200mW. The UCC39411
family also provides an auxiliary 7V output, primarily for the gate drive
supply, which can be used for applications requiring an auxiliary output,
such as 5V, by linear regulating. The primary output will start up under full
load at input voltages typically as low as 0.8V with a guaranteed max of
1V, and will operate down to 0.5V once the converter is operating,
maximizing battery utilization.
• 200mW Output Power at Battery
Voltages as low as 0.8V
• Secondary 7V Supply from a Single
Inductor
• Output Fully Disconnected in
The UCC39411 family is designed to accommodate demanding
applications such as pagers and cell phones that require high efficiency
over a wide operating range of several milli-watts to a couple of hundred
milli-watts. High efficiency at low output current is achieved by optimizing
switching and conduction losses with a low total quiescent current (50µA).
At higher output current the 0.5Ω switch, and 1.2Ω synchronous rectifier
along with continuous mode conduction provide high power efficiency. The
wide input voltage range of the UCC39411 family can accommodate other
power sources such as NiCd and NimH.
Shutdown
• Adaptive Current Mode Control for
Optimum Efficiency
• High Efficiency over Wide Operating
Range
• 6µA Shutdown Supply Current
• Output Reset Function with
Programmable Reset Period
The 39411 family also provides shutdown control. Packages available are
the 8 pin SOIC (D), 8 pin DIP (N or J), and 8 pin TSSOP (PW) to optimize
board space.
SIMPIFIED BLOCK DIAGRAM AND APPLICATION CIRCUIT (UCC39412)
+
22µH
100µF
SW
1V TO 3.5V
1
6
VIN
VGD
8
VOUT
3.3V 200mW
1.2Ω
7
100µF
100µF
START-UP
CIRCUITRY
0.5Ω
MODULATOR CONTROL CIRCUIT
R
RES
SYNCHRONOUS RECTIFICATION CIRCUITRY
ANTI-CROSS CONDUCTION
START-UP
MULTIPLEXING LOGIC
MAX INPUT POWER CONTROL
ADAPTIVE CURRENT CONTROL
RESB
CT
3
4
RESET CONTROL CIRCUIT
GLITCH SUPRESSION
SD/FB
2
PROGRAMMABLE TIMING
C
T
GND
5
UDG-98067
Note: Pinout shown is for the TSSOP Package. Consult Package Descriptions for DIP and SOIC configurations.
SLUS245A - MARCH 1999