参数资料
| 型号： | MC44605PG |
| 厂商： | ON Semiconductor |
| 文件页数： | 9/20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
(pin13)
pk
3
R
The Error Amp Output (Pin 13) is provided for external
loop compensation. The output voltage is offset by two
diodes drops ( [ 1.4 V) and divided by three before it
connects to the inverting input of the Current Sense
Comparator. This guarantees that no drive pulses appear at
the Source Output (Pin 3) when Pin 13 is at its lowest state
V * 1.4 V
I [
S
The Current Sense Comparator threshold is internally
clamped to 1.0 V. Therefore the maximum peak switch
current is:
S
(V OL ). This occurs when the power supply is operating and
the load is removed, or at the beginning of a soft ? start
interval. The Error Amp minimum feedback resistance is
I
pk(max)
+
1V
R
R1(min) +
+ 22 k Ω
limited by the amplifier’s minimum source current (0.2 mA)
and the required output voltage (V OH ) to reach the current
sense comparator ’s 1.0 V clamp level:
(3 1 V) ) 1.4 V
0.2 mA
Current Sense Comparator and PWM Latch
The MC44605 operates as a current mode controller. The
circuit uses a current sense comparator to compare the
inductor current to the threshold level established by the
Error Amplifier output (Pin 13). When the current reaches
the threshold, the current sense comparator terminates the
output switch conduction that has been initiated by the
Undervoltage Lockout Section
As depicted in Figure 3, an undervoltage lockout has been
incorporated to guarantee that the IC is fully functional
before allowing the system working.
In effect, the V CC is connected to the non inverting input
of a comparator that has an upper threshold equal to 14.5 V
(typical V stup ? th ) and a lower one equal to 7.5 V (typical
V disable 2 ). This hysteresis comparator enables or disables
the reference block that generates the voltage and current
sources required by the system.
This block particularly, produces V ref (pin 16 voltage) and
I ref that is determined by the resistor R ref connected between
pin 16 and the ground:
oscillator, by resetting the PWM Latch. Thus the error signal
controls the peak inductor current on a cycle ? by ? cycle
basis. This configuration ensures that only one single pulse
I
ref
+
V
R
ref where V
ref
ref
+ 2.5 V (typically)
appears at the Source Output during the appropriate
oscillator cycle.
V C
V in
V CC
(Pin 1)
V ref enable
R ref
Pin 16
PWM
C
1 0
UVLO
Dis out
V demag out
VS S
Q
Thermal R
Protection
Latch
Current Sense
Comparator
Substrate
14
R 2
3
Current
Sense
7
R 3
R
R S
Q1
1 0
V disable
7.5 V
C UVLO1
V disable1
9.0 V
C STARTUP
Reference Block:
Voltage and Current
Sources Generator
(V ref , I ref , ...)
STARTUP
14.5 V
UVLO1
(to SOFT ? START)
MC44605
Figure 3. V CC Management
Figure 2. Output Totem Pole
The inductor current is converted to a voltage by inserting
the ground referenced sense resistor R S in series with the
power switch Q1.
This voltage is monitored by the Current Sense Input
(Pin 7) and compared to a level derived from the Error Amp
output. The peak inductor current under normal operating
conditions is controlled by the voltage at Pin 13 where:
In addition to this, V CC is compared to a second threshold
level that is nearly equal to 9.0 V (V disable1 ) so that a signal
UVLO1 is generated to reset the soft ? start block and so, to
disable the output stage (refer to the Soft ? Start §) as soon as
V CC becomes lower than V disable 1 . In this way, the circuit
is reset and made ready for a next startup, before the
reference block is disabled (refer to Figure 3). Thus, finally
the upper limit for the minimum normal operating voltage
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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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