The JTM1538 uses a fixed frequency, peak current mode boost(2)

六.产品PDF文档

七,功能概述

The JTM1538 uses a fixed frequency, peak current mode boost regulator architecture to regulate voltage at the feedback pin. The operation of the JTM1538 can be understood by referring to the block diagram of Figure 3. At the start of each oscillator cycle the MOSFET is turned on through the control
circuitry. To prevent sub-harmonic oscillations at duty cycles greater than 50 per cent, a s tabilizing ramp is added to the output of the current sense amplifier and the result is fed into the negative input of the PWM comparator. When this voltage equals
the output voltage of the error amplifier the power MOSFET is turned off. The voltage at the output of the error amplifier is an am plified version of the
difference between the 1.25V bandgap referencevoltage and the feedback voltage. In this way the peak current level keeps the output in regulation. If the feedback voltage starts to drop, the output of the error amplifier increases. This results in more current to flow through the power MOSFET, thus increasing the power delivered to the output.
The JTM1538 has internal soft start to limit the amount of input current
at startup and to also limit the amount of overshoot on the output.

八,相关产品

内置MOS DC-DC 升压IC

型号	工作模式	工作	输出电压	输出电	输出电	内置MOS	效率	静态	工作频率	封装	直接替代型号
		电压范围		压形式	压精度	最大输		电流
						出电流
JTMXX1C	PFM	0.8V-Vout	2.2/2.7/2.8	固定输出	±2%	500mA	85%	4uA	350KHz	SOT-89	XC6382/XC6371/
			3.0/3.3/							SOT23-3L	RT9261B/HT77XX/
			3.6/4.0/5.0V							TO-92	BL8530/AIC1642/
											S8351
JTM1538	PWM	2.5V-6.0V	最大28V	可调输出	±2%	1.5A	90%	1uA	1.2MHz	SOT-25	AT1308/LTC1615/AP3012
	PFM										AIC1896/LM2703/ACT6311/APW7137/
											LM2731/TPS61040/MP1540/1/RT9284A/
											G5103/G5125/XC9119/AP1522/EUP2571/
JTM1548	PWM	2.5V-6.0V	最大12V	可调输出	±2%	3.5A	95%	1uA	1.2MHz	SOT-26	SY7208/SY7152/
	PFM										LTC3426/TPS6107X
JTM1548B	PWM	2.0V-24V	最大28V	可调输出	±2%	4A	97%	0.1uA	1.2MHz	SOT-26	SY7208/SY7152/
	PFM										LTC3426/TPS6107X
JTM1558	PWM	2.5V-6.5V	最大8V	可调输出	±2%	5A	93%	100uA	1.2MHz	SOT-26	SY7208/SY7152/
											LTC3426/TPS6107X
JTM1547	PWM	2.3-6V	最大14V	可调输出	±2%	4A/带限	96%	0.1uA	1.2MHz	SOT-26	FP6291
						流保护
JTM6291	PWM	2.5V-6.0V	最大12V	可调输出	±2%	2A/带限	90%	200uA	1.2MHz	SOT-26	FP6291
						流保护
JTM1534	PWM	0.9V-6.0V	1.5V-12V	可调输出	±2%	4A	90%	0.5uA	1MHz	SOT-25
	PFM
JTM1615	PWM	1.2V-15V	最大34V	可调输出	±2%	350mA	80%	1uA	1MHz	SOT-25	LTC1615/AIC1896/AP5727
											LM2703/5/AT1308/G5125/LM2731/
											TPS61040/1/G5103/MP1540/1/RT9284A
											XC9119/MP1522/AP1522/EUP2571/
JTM9266	PWM	1.0V-10V	最大12V	可调输出	±2%	2.5A	92%	70uA	450KHz	SOT-26	RT9266/PT1301/
											AX1301
JTM6293	PWM	2.6V-6.0V	最大12V	可调输出	±2%	3.5A	90%	170uA	1MHz	ESOP-8	FP6293
JTM6293B	PWM	2.5V-6.0V	最大9V	可调输出	±2%	4.5A	95%	0.1uA	1MHz	ESOP-8	FP6298/FP6293
	PFM
JTM9225	PWM	2.5V-6.5V	最大8V	可调输出	±2%	5.5A	93%	100uA	1.2MHz	ESOP-8
JTM6297	PWM	3.6V-26V	最大60V	可调输出	±2%	2A	90%	70uA	400KHz	SOP-8
JTM6298	PWM	3.6V-36V	最大60V	可调输出	±2%	3A	92%	70uA	400KHz	TO252-5L
JTM6299	PWM	5V-45V	最大60V	可调输出	±2%	5A	94%	70uA	220KHz	TO263-5L

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