目录ycH嘉泰姆

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

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

  The CXSD62129 consists of two independent 1.5MHz constant frequency, current mode, and PWM step-down converters. Each converter integrates a main switch with a synchronous rectifier for high efficiency without an external Schottky diode. The CXSD62129 is ideal for powering portable equipment that runs from a single cell Lithium Ion (Li+) battery. Each converter can supply 1A of loadycH嘉泰姆
current from a 2.7V to 5.5V input voltage. The output volt age can be regulated as low as 0.6V. The CXSD62129 can also run at 100% duty cycle for low dropout applications.ycH嘉泰姆
二.产品特点(Features)ycH嘉泰姆

1A Output Current on Each ChannelycH嘉泰姆
2.7V to 5.5V Input Voltage RangeycH嘉泰姆
1.5MHz Constant Frequency OperationycH嘉泰姆
Low Dropout Operation at 100% Duty CycleycH嘉泰姆
Synchronous TopologyycH嘉泰姆
0.6V Low Reference VoltageycH嘉泰姆
Current Mode OperationycH嘉泰姆
Over-Temperature ProtectionycH嘉泰姆
Over-Current ProtectionycH嘉泰姆
Up to 94% EfficiencyycH嘉泰姆
Internally CompensatedycH嘉泰姆
Lead Free and Green Devices AvailableycH嘉泰姆
(RoHS Compliant)ycH嘉泰姆
三,应用范围 (Applications)ycH嘉泰姆

TV Tuner/BoxycH嘉泰姆
Portable InstrumentycH嘉泰姆
四.下载产品资料PDF文档 ycH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！ycH嘉泰姆

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五,产品封装图 (Package)ycH嘉泰姆

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六.电路原理图ycH嘉泰姆

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七,功能概述ycH嘉泰姆

Main Control LoopycH嘉泰姆

The CXSD62129 has dual independent constant frequency,current-mode PWM step-down converters. During nor-ycH嘉泰姆
mal operation, the internal P-channel power MOSFET is turned on each cycle when the oscillator sets an internalycH嘉泰姆
RS latch and is turned off when an internal comparator (ICMP) resets the latch. The peak inductor current at whichycH嘉泰姆
ICMP resets the RS latch is controlled by the voltage on the COMP, which is the output of the error amplifierycH嘉泰姆
(EAMP). An external resistive divider connected between VOUT and ground allows the EAMP to receive an outputycH嘉泰姆
feedback voltage VFB at FB pin. When the load current increases, it causes a slightly decrease in VFB associatedycH嘉泰姆
with the 0.6V reference, which in turn causes the COMP voltage to increase until the average inductor currentycH嘉泰姆
matches the new load current.ycH嘉泰姆
Soft-StartycH嘉泰姆
Each channel in the CXSD62129 has a built-in soft-start to control the output voltage rise during start-up. During soft-start, an internal ramp, connected to the one of the posi- tive inputs of the error amplifier, raise up to replace the reference voltage (0.6V typical) until the ramp voltage reaches the reference voltage.ycH嘉泰姆
Short Circuit ProtectionycH嘉泰姆
For each channel, when the output is shortened to the ground, the frequency of the oscillator will be reduced toycH嘉泰姆
210kHz. This lower frequency allows the inductor current to safely discharge, thereby preventing current runaway.ycH嘉泰姆
The oscillator’s frequency will gradually increase to its designed rate when the feedback voltage on the FB againycH嘉泰姆
approaches 0.6V.ycH嘉泰姆
Over-Temperature Protection (OTP)ycH嘉泰姆
For each channel, the over-temperature circuit limits the junction temperature of the CXSD62129. When the junction temperature exceeds 150oC, a thermal sensor turns off the power MOSFETs, allowing the channels to cool down.The thermal sensor allows the converter to start a soft- start process and to regulate the output voltage againycH嘉泰姆
after the junction temperature cools by 40ïC. The OTP is designed with a 40ïC hysteresis to lower the averageycH嘉泰姆
Junction Temperature (TJ) during continuous thermal overload conditions, increasing the lifetime of the device. ycH嘉泰姆
Enable/ShutdownycH嘉泰姆
For each channel, driving EN to the ground places the channel in shutdown mode. When in shutdown, the inter-ycH嘉泰姆
nal power MOSFETs are turned off, all internal circuitry shuts down, and the quiescent supply current reduces toycH嘉泰姆
1μA maximally. ycH嘉泰姆
Automoatic PFM/PWM mode SwitchycH嘉泰姆
The CXSD62129 is a fixed frequency PWM peak current modulation control step-down converter. At light loads,ycH嘉泰姆
the CXSD62129 will automatically enter in pulse frequency modulation operation to reduce the dominant switchingycH嘉泰姆
losses. In PFM operation, the inductor current may reach zero or reverse on each pulse. A zero current comparatorycH嘉泰姆
turns off the N-channel synchronous MOSFET, forcing DCM (Discontinuous Current Mode) operation at lightycH嘉泰姆
load. These controls get very low quiescent, help to main- tain high efficiency over the complete load range.ycH嘉泰姆

八,相关产品                 更多同类产品.......ycH嘉泰姆

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