中文
EnglishCXSD62129由两个独立的1.5MHz恒定频率电流模式和PWM降压转换器组成同步整流器
目录
1.产品概述 2.产品特点
3.应用范围 4.下载产品资料PDF文档
5.产品封装图 6.电路原理图
7.功能概述 8.相关产品
一,产品概述(General Description)
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 load
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.
二.产品特点(Features)
1A Output Current on Each Channel
2.7V to 5.5V Input Voltage Range
1.5MHz Constant Frequency Operation
Low Dropout Operation at 100% Duty Cycle
Synchronous Topology
0.6V Low Reference Voltage
Current Mode Operation
Over-Temperature Protection
Over-Current Protection
Up to 94% Efficiency
Internally Compensated
Lead Free and Green Devices Available
(RoHS Compliant)
三,应用范围 (Applications)
TV Tuner/Box
Portable Instrument
四.下载产品资料PDF文档
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！
五,产品封装图 (Package)
六.电路原理图
七,功能概述
Main Control Loop
The CXSD62129 has dual independent constant frequency,current-mode PWM step-down converters. During nor-
mal operation, the internal P-channel power MOSFET is turned on each cycle when the oscillator sets an internal
RS latch and is turned off when an internal comparator (ICMP) resets the latch. The peak inductor current at which
ICMP resets the RS latch is controlled by the voltage on the COMP, which is the output of the error amplifier
(EAMP). An external resistive divider connected between VOUT and ground allows the EAMP to receive an output
feedback voltage VFB at FB pin. When the load current increases, it causes a slightly decrease in VFB associated
with the 0.6V reference, which in turn causes the COMP voltage to increase until the average inductor current
matches the new load current.
Soft-Start
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.
Short Circuit Protection
For each channel, when the output is shortened to the ground, the frequency of the oscillator will be reduced to
210kHz. This lower frequency allows the inductor current to safely discharge, thereby preventing current runaway.
The oscillator’s frequency will gradually increase to its designed rate when the feedback voltage on the FB again
approaches 0.6V.
Over-Temperature Protection (OTP)
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 again
after the junction temperature cools by 40ïC. The OTP is designed with a 40ïC hysteresis to lower the average
Junction Temperature (TJ) during continuous thermal overload conditions, increasing the lifetime of the device.
Enable/Shutdown
For each channel, driving EN to the ground places the channel in shutdown mode. When in shutdown, the inter-
nal power MOSFETs are turned off, all internal circuitry shuts down, and the quiescent supply current reduces to
1μA maximally.
Automoatic PFM/PWM mode Switch
The CXSD62129 is a fixed frequency PWM peak current modulation control step-down converter. At light loads,
the CXSD62129 will automatically enter in pulse frequency modulation operation to reduce the dominant switching
losses. In PFM operation, the inductor current may reach zero or reverse on each pulse. A zero current comparator
turns off the N-channel synchronous MOSFET, forcing DCM (Discontinuous Current Mode) operation at light
load. These controls get very low quiescent, help to main- tain high efficiency over the complete load range.
八,相关产品 更多同类产品.......
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Switching Regulator > Buck Converter |
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|
Part_No |
Package |
Architectu |
No.of PWM Outpu |
Drive Lout (A) |
Vin(V) |
Fmax Khz |
Vref (V) |
R-Top (milohm) |
R-Sync (milohm) |
Iq (No load) (uA) |
|
|
min |
max |
||||||||||
|
TQFN5x6-28 |
CM |
1 |
5 |
4.5 |
26 |
380 |
0.8 |
50 |
20 |
1000 |
|
|
SOP-8 |
CM |
1 |
2 |
4.5 |
26 |
380 |
0.8 |
100 |
1000 |
||
|
SOP-8P |
CM |
1 |
4 |
4.5 |
26 |
380 |
0.8 |
80 |
1000 |
||
|
SOT23-5|TSOT23-5 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
SOT23-5 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
SOP-8 |
CM |
1 |
3 |
4.3 |
14 |
500 |
0.8 |
70 |
70 |
500 |
|
|
SOP-8P |
CM |
1 |
3 |
4.3 |
14 |
500 |
0.8 |
55 |
45 |
500 |
|
|
TDFN3x3-10 |
3 |
2.6 |
5.5 |
2000 |
0.8 |
110 |
110 |
460 |
|||
|
TDFN3x3-10 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
500 |
|
|
TDFN3x3-10 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN2x2-6 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
TDFN2x2-6 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN3x3-12 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
TDFN3x3-12 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN 3x3 12 |
CM |
2 |
1 |
3 |
5.5 |
1500 |
0.6 |
280 |
250 |
30 |
|
|
TQFN3x3-20 |
CM |
3 |
2 |
2.9 |
5.5 |
1500 |
0.6 |
- |
- |
300 |
|
|
TDFN2x2-8 |
CM |
1 |
1 |
3.3 |
8 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
SOP-8 |
CM |
1 |
2 |
4.5 |
24 |
340 |
0.925 |
110 |
110 |
1900 |
|
|
SOP-8P |
CM |
1 |
3 |
4.5 |
24 |
340 |
0.925 |
110 |
110 |
1900 |
|
|
SOP-8 |
CM |
1 |
2 |
4.5 |
24 |
340 |
0.92 |
130 |
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