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参数资料
| 型号： | LTC3459EDCB#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 0.09 A SWITCHING REGULATOR, PDSO6 |
| 封装： | 2 X 3 MM, LEAD FREE, PLASTIC, MO-229, DFN-6 |
| 文件页数： | 10/12页 |
| 文件大小： | 216K |
| 代理商： | LTC3459EDCB#PBF |
LTC3459
7
3459fc
OPERATION
Operation
The LTC3459 synchronous boost converter utilizes a
Burst Mode control technique to achieve high efciency
over a wide dynamic range. A 2.5% accurate comparator
is used to monitor the output voltage (VOUT), if VOUT is
above the comparator threshold, no switching occurs and
only quiescent current (10μA) is drawn from the power
source. When VOUT dropsbelowthecomparatorthreshold,
switching commences and the output capacitor is charged.
During the on time of the switching period, inductor cur-
rent is ramped through an internal N-channel MOSFET to
GND until a peak current (75mA) is detected. A P-channel
MOSFET connects the inductor to VOUT during the off time
delivering energy to the load. The off time is controlled by
an internal timer which is proportional to 1/(VOUT – VIN).
Anticross conduction circuitry ensures the N- and P-chan-
nel switches are never on simultaneously.
Only three power components and two feedback resistors
are required to complete the design of the boost converter,
an external Schottky diode is not required. The high op-
erating frequency allows the use of low value, low prole
inductors and tiny external ceramic capacitors. The boost
converter disconnects VOUT from VIN during shutdown to
avoid loading the input power source.
Peak Current Overshoot
The LTC3459’s peak current comparator has a delay of ap-
proximately 100ns from the time inductor current reaches
current limit until the internal N-channel MOSFET turns off.
This delay causes the peak current to overshoot based on
the inductor value and VIN, as follows (Figure 2 is based
on a 65mA initial ILIMIT).
II
ns
V
L
PEAK
LIMIT
IN
=+
()
100
tOFF Timer
The LTC3459’s tOFF timer is designed to keep the inductor
current continuous during a Burst Mode switching packet,
thereby increasing current capability at the output. A larger
inductor value will have lower peak-to-peak current ripple,
increasing the available current to the load. This improve-
ment is offset somewhat by the reduced IPEAK overshoot.
The tOFF timer is designed to maintain a relatively constant
peak-to-peak current in the inductor despite VIN changes.
Figure 1. Inductor Current and VOUT Ripple Waveforms
Figure 2. Typical IPEAK Values
Figure 3. tOFF Times
VOUT
AC
RIPPLE
IPEAK
3459 F01
~50mVP-P
~100mA
SLEEP
IZERO WAIT
BURST ON
tOFF
P
tOFF
PP
tOFF
P
tOFF
P
NN
N
BURST ON
VIN (V)
1.5
60
50
I PEAK
(mA)
70
80
90
100
2.5
3.5
4.5
5.5
3459 F02
110
23
4
5
15μH
22μH
33μH
VOUT – VIN (V)
0.5
0
t OFF
(μs)
0.1
0.3
0.4
0.5
0.7
2.5
4.5
5.5
3459 F03
0.2
0.8
0.6
1.5
3.5
6.5
7.5
8.5
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3459EDCB-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:10V Micropower Synchronous Boost Converter |
| LTC3459EDCPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:10V Micropower Synchronous Boost Converter |
| LTC3459EDC-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:10V Micropower Synchronous Boost Converter |
| LTC3459EDC-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:10V Micropower Synchronous Boost Converter |
| LTC3459ES6 | 制造商:LINER 制造商全称:Linear Technology 功能描述:10V Micropower Synchronous Boost Converter in ThinSOT |
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