In power supply applications that require a wide input voltage range, high efficiency, and multiple protections, the four switch buck boost DC-DC chip CXSU63303 is an ideal choice for industrial control, mobile energy storage, and electric vehicles due to its outstanding performance. This article will provide an in-depth analysis of its technical characteristics, working principles, and design points to assist engineers in optimizing power system design.
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[ CXSU63303 ]"
CXSU63303: Innovative Power Management Core for Wide Voltage Applications
In power supply application scenarios that require a wide input voltage range, high efficiency, and multiple protections,Four switch buck boost DC-DC chip CXSU63303With its outstanding performance, it has become an ideal choice for industrial control, mobile energy storage, and electric transportation. This article will provide an in-depth analysis of its technical characteristics, working principles, and design points to assist engineers in optimizing power system design.
1、 Core Features and Advantages
CXSU63303 integrates multiple innovative technologies to meet demanding application requirements:
1. Ultra wide input voltage range(7V-150V): Suitable for severe fluctuations in battery voltage (such as 12V-60V for lithium battery packs), especially suitable for unstable power supply scenarios such as solar energy input and electric vehicle systems.
2.95% ultra-high conversion efficiency:The synchronous rectification architecture significantly reduces losses and significantly improves battery life.
3. Multiple protection mechanisms
a. Input undervoltage/output short circuit protection
b. Over temperature shutdown (threshold 234.7mV,& amp; amp; 125℃）
c. Anti backflow startup mode (configured through STMOD pin)
4. Support battery charging:Built in constant voltage and current control, can be directly used for energy storage system charging management.
5. QFN32 Compact Package:5mm× 5mm miniaturization design saves PCB space.
2、 Key Technology Analysis
1. Adaptive Voltage Boosting Control
CXSU63303 automatically switches operating modes based on input/output voltage relationship:
a. Voltage reduction modeLeft bridge arm PWM dynamic voltage regulation, right bridge arm fixed conduction
b. Boost modeLeft bridge arm fixed conduction, right bridge arm PWM dynamic voltage regulation
Seamless switching technologyEnsure uninterrupted output during input voltage fluctuations, especially suitable for electric bicycle battery systems in motion.
2. Precise voltage/current control
| parameter | configuration method | calculation formula | Example (15V/10A output) |
|---|---|---|---|
| output voltage | VOUTFB voltage divider resistor | Vout=(1+R1/R2)× 1.36V | R1=10kΩ , R2=1kΩ → 14.96V |
| output current | IFB+/IFB differential amplifier+external sampling resistor | I=0.976/(G×Rsamp) | Rsamp=5mΩ , G=19.8 → 10.1A |
3. Selection of key peripheral components
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Inductance design：
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Voltage reduction mode:
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Boost mode:
*Suggestion: Ripple currentΔ I ≤ 30% maximum output current, Fs=70kHz*
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Capacitor selection：
Low ESR capacitance is crucial, ripple voltage formula:
3、 Typical application scenarios
1. Electric bicycle converter:Compatible with lead-acid/lithium battery packs (24V-72V), supporting brake energy recovery.
2. Mobile energy storage power supply:12V/24V battery charging and discharging management, supporting solar MPPT input (CXSU63303-B exclusive).
3. Industrial control system:Wide voltage input (24V/48V industrial bus) to stable 12V/5V, resistant to voltage surges.
4. Telecommunications power backup system:-48V to 12V redundant power supply, short circuit protection to prevent equipment damage.
Application CasesThe 15V/50A high-power scheme (Figure 6-2) is implemented through external MOS expansion to meet the requirements of high-power energy storage inverters.
4、 Deep optimization of security protection mechanism
1. Short circuit protectionAfter triggering, lock for 5 seconds and automatically restart to avoid continuous overload
2. Temperature protection：
a. Built in sensor detects TFB pin voltage
b.< Turn off PWM at 0.2347V (approximately 125 ℃)
c. Automatic recovery of temperature drop
3. Anti backflow designSTMOD pin grounded to suppress current backflow during startup
5、 Packaging and Electrical Specifications
| parameter | minimum | typical value | maximum | unit |
|---|---|---|---|---|
| Operating Temperature | -40 | - | one hundred and five | ℃ |
| VDD12 voltage | seven | twelve | twenty | V |
| dead time | - | three hundred | - | ns |
| Drive current capability | - | ± 1A | - | - |
Packaging Details：QFN32 (5mm×5mm×0.75mm)， The bottom heat dissipation pad needs to be strengthened with thermal design.
Application Design Circuit Component Parameter Selection
1 PWM modulation
CXSU63303 Automatically operate in a step-down or step-up state based on the specific relationship between input and output voltages and different load conditions. Upper and lower pipes; PWM complementary
Implement synchronous streaming. During voltage reduction, the left bridge arm; PWM The duty cycle is controlled by the voltage current loop, and the right bridge arm has a fixed output. When boosting, the left bridge arm is fixed,
Right bridge arm; PWM The duty cycle is controlled by the voltage current loop. It can achieve seamless automatic connection between voltage reduction and boost when the input voltage changes. In charging applications
Suggested occasions; 16 pin grounding, suppresses backflow during startup. When the output experiences a long time reversal, the tube on the right bridge arm closes and automatically opens upon recovery.
2 Output voltage setting
CXSU63303 The output voltage is determined by; VOUTFB The two voltage divider resistors on the pins are set, and the reference voltage of the internal error amplifier is; 1.36V， as
Figure 8.1 As shown, the output voltage; Vout=（ 1+R1/R2 ）*1.36V， To set the output voltage to; 14.96V， Can be set; R1 For 10K ，R2 for
1K， Output voltage; Vout=（1+10/1）*1.3630V=14.96V。
3 Output current settings
CXSU63303 It is done through pins; 2、3 Forming a differential amplifier with an internal operational amplifier to process the output current signal. Internal amplifier
Structure as shown in the diagram; 8-2 As shown, the feedback resistance is; 200K：10K。 In general application scenarios, the two in the figure; R It is a resistor that needs to be placed outside the chip,
R0 Form a first-order RC filtering, with a final amplification factor of; G=R4/(R3+R0)。
For example; Rsamp=0. 005Ω ， R4=200KΩ ， R3=10KΩ ， R0=0. 1KΩ ， G=R4/(R3+R0)=200KΩ /(10KΩ+0. 1KΩ)=19. 8，
I=0. 976/(G*Rsamp)=1. 00/(19. 8* 0. 005)=10. 1A。
4 Output inductance
CXSU63303 The switch frequency is fixed, and the value of the inductor directly affects the operation of the converter, which will affect the ripple of the inductor current.
The selection of inductance for voltage reduction mode can be based on the following formula:
In the equation, Vin It is the input voltage, Vout It is the output voltage,Fs Yes PWM Working frequency, Iripple The peak to peak value of the current ripple in the inductor is usually selected; Iripple Not exceeding the maximum output current; 30%.
The selection of boost mode inductance can be based on the following formula:;
In the equation, Vin It is the input voltage, Vout It's an outputVoltage, Vdiode It is synchronous rectification; MOS Tube conduction pressure difference, Fs Yes PWM Working frequency, Iripple It is the peak to peak value of the current ripple in the inductor
Frequently selected; Iripple Not exceeding the maximum output current; 30%.
5 output capacitor
Output capacitance; Co Used to filter the output voltage, so that; The DC-DC converter outputs a relatively stable DC power to the load, and this power is selected
Choose as low a time as possible; ESR The size of the selected capacitance value is mainly determined by the ripple requirements of the output voltage, which can be determined by the following formula:
, whereΔ Vo It is the output voltage ripple,Δ IL It is the ripple of inductor current, Fs Yes PWM Working frequency, ESR It's a lossEquivalent series resistance of output capacitor.
6 output short circuit
When the output is short circuited, CXSU63303 Operate at maximum peak current limit output, while reducing the output voltage to below one fourth of the rated value, i.e. touch
Lock after protection and short circuit protection; 5s Restart afterwards.
7 over-temperature protection
CXSU63303 has an internally set temperature protection threshold of 0.2347V. When the voltage of the temperature detection pin is less than this value, the over temperature protection is triggered, and PWM is used at this time
Output turned off, automatically restored after temperature drop.
Conclusion: Redefine power flexibility
CXSU63303 passedFour switch topology innovationSolved the pain points of low efficiency and switching blind spots in traditional Buck Boost circuits. Its 150V withstand voltage, 95% efficiency, and intelligent protection features provide power for battery supply systems; No feeling "; Voltage adaptability. With the popularization of portable devices and green energy, this chip will continue to release technological dividends in the fields of electric transportation and smart energy storage.
Technical Specifications (Product PDF)*Design Tip: CXSU63303-B version should be preferred as it supports photovoltaic constant voltage input. Please note that the bootstrap capacitor (VB1/VB2 pins) should be a high-voltage ceramic capacitor*
For detailed PDF specifications, please scan WeChat to contact us. You can also receive free samples and technical support！
Product packaging diagram;
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