目录jbf嘉泰姆

1.产品概述                       2.产品特点jbf嘉泰姆
3.应用范围                       4.下载产品资料PDF文档 jbf嘉泰姆
5.产品封装图                     6.电路原理图                   jbf嘉泰姆
7.功能概述                        8.相关产品jbf嘉泰姆

一,产品概述(General Description)         jbf嘉泰姆

    CXLE8854B is a wide input voltage, high efficiency CC and CV step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode.jbf嘉泰姆
   CXLE8854B provides low-ripple power, high efficiency, and excellent transient characteristics.The PWM control circuit is able to the duty ratio linearly forms 0 up to 90%. An over current protection and short circuit protection functions are built outside that it can set by a resistance. An external compensation is easily to system stable;the low ESR output capacitor can be used.With the addition of an internal N-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators.jbf嘉泰姆

    They serve as ideal power supply units for portable devices when coupled with the SOP-8L and SOP-8L-EP packages, providing such outstanding features as low current consumption. Since this converter can accommodate an input oltage up to 40V, it isalso suitable for the operation via an AC adapterjbf嘉泰姆
二.产品特点(Features)jbf嘉泰姆

 Perfect Solution for Car Chargerjbf嘉泰姆
Input Voltage：7V to 40Vjbf嘉泰姆
High CC accuracy ±5%jbf嘉泰姆
High CV accuracy ±2%jbf嘉泰姆
Duty ratio：0% to 90% PWM controljbf嘉泰姆
Oscillation frequency：jbf嘉泰姆
120K Hz for  Ajbf嘉泰姆
250K Hz for       Bjbf嘉泰姆
Thermal Shutdown function.jbf嘉泰姆
Short Circuit Protect (SCP).jbf嘉泰姆
Built-in internal SW N-channel MOS.jbf嘉泰姆
Current mode non-synchronous PWM converterjbf嘉泰姆
Cycle to cycle Current Limitingjbf嘉泰姆
External current limit setting.jbf嘉泰姆
Under Voltage Lockout.jbf嘉泰姆
Over Voltage Protection.jbf嘉泰姆
三,应用范围 (Applications)jbf嘉泰姆
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四.下载产品资料PDF文档jbf嘉泰姆

 需要详细的PDF规格书请扫一扫微信联系我们，还可以获得免费样品以及技术支持！jbf嘉泰姆

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 五,产品封装图 (Package)jbf嘉泰姆

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六.电路原理图jbf嘉泰姆

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七,功能概述jbf嘉泰姆

As seen in Functional Block Diagram, the CXLE8854B is a peak current mode pulse width modulationjbf嘉泰姆
(PWM) converter with CC and CV control. The converter operates as follows:jbf嘉泰姆
A switching cycle starts when the rising edge of the Oscillator clock output causes thejbf嘉泰姆

High-Side Power Switch to turn on. With the SW side of the inductor now connected to Sense1, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higherthan the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes low, the High-Side Power Switch turns off.jbf嘉泰姆
At this point, the SW side of the inductor swings to a diode voltage below ground, causing thejbf嘉泰姆
inductor current to decrease and magnetic energy to be transferred to output. This state continues untilthe cycle starts again. The High-Side Power Switch is driven by logic using BS as the positive rail. This pin is charged to VSW + 5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 1V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Output current will increase until it reaches the CC limit set by the R1 resistor. At this point, the device will transition from regulating output voltage to regulating output current, and the output voltage will drop with increasing load.jbf嘉泰姆
The Oscillator normally switches at 200KHz. However, if FB voltage is less than 0.45V, then thejbf嘉泰姆
switching frequency decreases until it reaches a typical value of 30KHz at VFB = 0.15Vjbf嘉泰姆
八,相关产品                 更多同类产品......jbf嘉泰姆