参数资料
| 型号： | MC44605PG |
| 厂商： | ON Semiconductor |
| 文件页数： | 10/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBK ISO PWM 16DIP |
| 产品变化通告： | Product Obsolescence 19/Dec/2008 |
| 标准包装： | 500 |
| 系列： | GreenLine™ |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 250kHz |
| 占空比： | 80% |
| 电源电压： | 10 V ~ 15 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： | 16-DIP（0.300"，7.62mm） |
| 包装： | 管件 |
| 其它名称： | MC44605PGOS |
MC44605
is 9.4 V (maximum value of V disable 1 ) and so the minimum
hysteresis is 4.2 V. [(V stup ? th ) min = 13.6 V].
The large hysteresis and the low startup current of the
MC44605 make it ideally suited for off ? line converter
applications where efficient bootstrap startup techniques are
required.
Soft ? Start Control Section
The V cs value is clamped down to the pin 11 voltage.
So, if a capacitor is connected to this pin, its voltage
increases slowly at the startup (the capacitor is charged by
an internal current source 0.4 I ref ). So, V cs is limited during
the startup and then a soft ? start is performed.
This pin can be used to inhibit the circuit by applying a
voltage that is lower than V SSinhi (refer to page 4).
Particularly, the MC44605 can be shutdown by connecting
the soft ? start pin to ground.
As soon as V dis1 is detected (that is V cc lower than
V disable1 ), a signal UVLO1 is generated until the V cc falls
down to V dis2 (refer to the undervoltage lockout section §).
During the delay between the disable1 and the disable2,
using a transistor controlled by UVLO1, the pin 11 voltage
is made equal to zero in order to make the soft ? start
arrangement ready to work for the next re ? start.
The MC44605 oscillator achieves four functions:
— it fixes the free mode frequency
— it takes into account the synchronization signal
— it does not allow a new power switch conduction if the
flyback is not in a dead ? time state when the circuit
works in demagnetization mode (pin 8 connected)
— it builds the Sf pulse required by the MPL block
During the operating mode, the oscillator sawtooth can
vary between a valley value (1.6 V typically) and a peak one
(3.6 V typically) and presents three distinct phases:
— the C T charge
— the C T discharge
— the phase during which the oscillator voltage is
maintained equal to its valley value. This happens at
the end of a discharge cycle when the synchronization
or demagnetization condition does not allow a new C T
charge phase. During this sequence, I REGUL
compensates the charge current I charge .
The oscillator has two working modes:
— a free one when there is no synchronization
— a synchronized one.
In the free working, the oscillator grows up from its valley
value to its peak one for the charge phase and when once the
peak value is reached, a discharge sequence makes the C T
voltage decrease down to its valley value. When the
Pin 11
Soft
Start
Capacitor
D Z
V ref
2.4 V
0.4 I ref
UVLO1
V SSlnhi
MC44605
Vcs
Output
Inhibition
decrease phase is finished, a new charge cycle occurs if the
demagnetization condition is achieved (V DT high).
Otherwise there is a REGUL phase until V DT gets high.
In the synchronized mode, the charge cycle is only
allowed when the synchronization signal gets high while a
dead time has been detected (V DT high). This charge phase
is stopped when the synchronization signal has got low and
when the oscillator voltage is higher than V int , the
intermediary voltage level used to generate the calibrated
pulse Sf by comparing the C T voltage to this threshold. So,
when these two conditions are performed, a discharge
sequence is set until the oscillator voltage is equal to its
Figure 4. Soft ? Start
valley value. Then, the C T voltage is maintained constant
thanks to the “REGUL” arrangement until the next
synchronization pulse.
Oscillator Section (Figures 5 & 5b)
The oscillator and synchronization
represented in Figure 5b.
behavior
is
In both cases, during the charge phase, a signal V S is
generated. When Sf becomes high. V S gets high and remains
in this state until the PWN latch is set of Sf is low. Then, V S
keeps low until the next Sf high level. This oscillator
behavior is obtained using the process described in
Figure 5b.
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| MC44608P100 | 功能描述:IC REG CTRLR FLYBK ISO PWM 8-DIP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| MC44608P40 | 功能描述:电压模式 PWM 控制器 40KHz 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 |
| MC44608P40G | 功能描述:电压模式 PWM 控制器 40KHz 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 |
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