- 您现在的位置：买卖IC网 > PDF目录20383 > DC1227A (Linear Technology)BOARD EVALUATION FOR LTC3534 PDF资料下载
参数资料
| 型号： | DC1227A |
| 厂商： | Linear Technology |
| 文件页数： | 11/20页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION FOR LTC3534 |
| 设计资源： | DC1227A Design Files DC1227A Schematic |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步升/步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 5V |
| 电流 - 输出： | 500mA（最小值） |
| 输入电压： | 3.6 ~ 7 V |
| 稳压器拓扑结构： | 降压-升压 |
| 频率 - 开关： | 1MHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LTC3534 |
LTC3534
OPERATION
I OUT(MAX)BURST ? BOOST ≈
125 ? V IN
η ?I LOAD
25μA + I LOAD
In Burst Mode operation the typical maximum average
output currents in the three operating regions, buck, four
switch, and boost are given by:
I OUT(MAX)BURST–BUCK ≈ 100mA;
Burst Mode operation – buck region: V IN > V OUT
I OUT(MAX)BURST–FOUR_SWITCH ≈ 125mA;
Burst Mode operation – four switch region: V IN ≈ V OUT
mA;
V OUT
Burst Mode operation – boost region: V IN < V OUT
The efficiency below 1mA becomes dominated primarily
by the quiescent current. The Burst Mode operation ef-
ficiency is given by:
Efficiency ?
where h is typically 90% during Burst Mode operation.
A graph of Burst Mode operation maximum output current
vs V IN (for V OUT = 5V) is provided in the Typical Perfor-
mance Characteristics section.
Burst Mode Operation to Fixed Frequency Transient
Response
In Burst Mode operation, the compensation network is
not used and V C is disconnected from the error amplifier.
V IN
13
During long periods of Burst Mode operation, leakage
currents in the external components or on the PC board
could cause the compensation capacitor to charge (or
discharge), which could result in a large output transient
when returning to fixed frequency mode operation, even
at the same load current. To prevent this, the LTC3534
incorporates an active clamp circuit that holds the voltage
on V C at an optimal voltage during Burst Mode operation.
This minimizes any output transient when returning to
fixed frequency mode operation. For optimum transient
response, Type III compensation is also recommended
to broad band the control loop and roll off past the two
pole response of the output LC filter. (See Closing the
Feedback Loop).
Soft-Start
The soft-start function is combined with shutdown. When
the RUN/SS pin is brought above 1V typical, the LTC3534
is enabled but the error amplifier duty cycle is clamped
from V C . A detailed diagram of this function is shown in
Figure 3. The components R SS and C SS provide a slow
ramping voltage on RUN/SS to provide a soft-start func-
tion. To ensure that V C is not being clamped, RUN/SS
must be raised to 2.4V or above. The IC must be enabled
(even with a soft-start) commanding PWM mode. Once
the LTC3534 is in regulation, then Burst Mode operation
can be commanded.
ENABLE
SIGNAL
R SS
RUN/SS
2
C SS
+
ERROR
AMP
–
1V
FB
15
V OUT
11
R1
CHIP
ENABLE
+
–
1V
V CI
TO PWM
COMPARATORS
V C
14
C P1
R2
3534 F03
Figure 3. Soft-Start Circuitry
3534fb
For more information www.linear.com/LTC3534
11
相关PDF资料 |
PDF描述 |
|---|---|
| EL7212CS-T7 | IC DRIVER MOSFET DUAL HS 8-SOIC |
| ES1D-13 | RECT SUPER FAST SMD 200V 1A SMA |
| SDR1005-150ML | INDUCTOR PWR 15.0UH SMD |
| FPI | AC ADAPTER CLIP - INDIA |
| VE-B6J-CX-F1 | CONVERTER MOD DC/DC 36V 75W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DC1-2-28/12A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
| DC1-2-28/15A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
| DC1-2-28/24A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
| DC1-2-28/5A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
| DC1-2-28/9A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC |
发布紧急采购，3分钟左右您将得到回复。