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参数资料
| 型号： | MC44608P40G |
| 厂商： | ON Semiconductor |
| 文件页数： | 6/15页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBK ISO PWM 8-DIP |
| 产品变化通告： | Product Obsolescence 01/Jul/2009 |
| 标准包装： | 50 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 44kHz |
| 占空比： | 86% |
| 电源电压： | 6.6 V ~ 13 V |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -25°C ~ 85°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 包装： | 管件 |
| 其它名称： | MC44608P40GOS |
MC44608
In standby mode, this current can be lowered as due to the
Oscillator Buffer Output
1 ? (R cs(k Ω ) × 0, 2)
max ? stby
R sense( Ω )
activation of a 200 m A current source:
Ipk =
(A)
R Q
DMG
S
Demag
Switching Phase
DMG
&
+
--
50/20 mV
1
1
200 m A
0
&
STANDBY
STARTUP
> 24 m A
>120 m A
Idemag
Current Mirror
Isense
L.E.B.
Overcurrent
Comparator
Figure 4. Demagnetization Block
Rsense
Rcs
2
+
--
OC
This function can be inhibited by grounding it but in this
case, the quick and programmable OVP is also disabled.
1V
Figure 3. Current Sense
The current sense input consists of a filter (6.0 k Ω , 4.0 pF)
and of a leading edge blanking. Thanks to that, this pin is not
sensitive to the power switch turn on noise and spikes and
practically in most applications, no filtering network is
required to sense the current.
Oscillator
The MC44608 contains a fixed frequency oscillator. It is
built around a fixed value capacitor CT successively
charged and discharged by two distinct current sources ICH
and IDCH. The window comparator senses the CT voltage
value and activates the sources when the voltage is reaching
the 2.4 V/4.0 V levels.
Finally, this pin is used:
-- as a protection against over currents (Isense > I)
-- as a reduction of the peak current during a Pulsed Mode
switching phase.
The overcurrent propagation delay is reduced by
producing a sharp output turn off (high slew rate). This
results in an abrupt output turn off in the event of an over
current and in the majority of the pulsed mode switching
DMG
from Demag
logic block
&
ICH
SDCH
SCH
4V
2.4 V
Window
+ comp
--
OSC
Clock
sequence.
Demagnetization Section
The MC44608 demagnetization detection consists of a
IDCH
CT
comparator designed to compare the V CC winding voltage
to a reference that is typically equal to 50 mV.
This reference is chosen low to increase effectiveness of
the demagnetization detection even during startup.
A latch is incorporated to turn the demagnetization block
output into a low level as soon as a voltage less than 50 mV
is detected, and to keep it in this state until a new pulse is
generated on the output. This avoids any ringing on the input
signal which may alter the demagnetization detection.
For a higher safety, the demagnetization block output is
also directly connected to the output, which is disabled
during the demagnetization phase.
The demagnetization pin is also used for the quick,
Figure 5. Oscillator Block
The complete demagnetization status DMG is used to
inhibit the recharge of the CT capacitor. Thus in case of
incomplete transformer demagnetization the next switching
cycle is postpone until the DMG signal appears. The
oscillator remains at 2.4 V corresponding to the sawtooth
valley voltage. In this way the SMPS is working in the so
called SOPS mode (Self Oscillating Power Supply). In that
case the effective switching frequency is variable and no
longer depends on the oscillator timing but on the external
working conditions (Refer to DMG signal in the Figure 6).
programmable OVP. In fact, the demagnetization input
current is sensed so that the circuit output is latched off when
this current is detected as higher than 120 m A.
http://onsemi.com
6
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MC44608P75 | 功能描述:电压模式 PWM 控制器 75KHz High Voltage RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MC44608P75G | 功能描述:电压模式 PWM 控制器 75KHz High Voltage SMPS PWM RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MC4466 | 制造商:SHENZHENFREESCALE 制造商全称:ShenZhen FreesCale Electronics. Co., Ltd 功能描述:N-Channel 30-V (D-S) MOSFET High performance trench technology |
| MC4468 | 制造商:SHENZHENFREESCALE 制造商全称:ShenZhen FreesCale Electronics. Co., Ltd 功能描述:N-Channel 30-V (D-S) MOSFET High performance trench technology |
| MC44722A | 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:Advanced Digital Video Encoder |
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