In modern electronic devices, power conversion efficiency and volume have become key design considerations. As a high-performance, small-package current-mode boost converter, CXSU63309 is widely used in OLED bias, LCD power supply, white LED driver and various portable devices. This article will analyze the characteristics of the CXSU63309, working principle, design points and its advantages in practical applications, and help engineers to achieve a more efficient and compact power design.
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[ CXSU63309 ]"
CXSU63309: High Efficiency Boost Converter Based on 1.25V Reference
In modern electronic devices, power conversion efficiency and volume have become key design considerations. As a high-performance, small-package current-mode boost converter, CXSU63309 is widely used in OLED bias, LCD power supply, white LED driver and various portable devices. This article will analyze the characteristics of the CXSU63309, working principle, design points and its advantages in practical applications, and help engineers to achieve a more efficient and compact power design.
1. CXSU63309 Product overview
The CXSU63309 is a fixed-frequency, peak-current-controlled boost converter in a 5-pin SOT23-5 package for space-constrained, low-power applications. Its core features include:
Wide input voltage range: 2.5V to 5.5V, compatible with multiple battery types
High output voltage: Supports up to 28V output to meet high voltage bias requirements
high efficiency operation: Automatically switch to PFM mode at light load, the efficiency of the whole machine exceeds 85%
Low static power consumption: Quiescent current in PFM mode is only 40μA
High degree of integrationBuilt-in 0.5Ω power MOSFET, soft start, overcurrent and overtemperature protection
Fixed switching frequency: 1.2MHz, can use small size inductors and capacitors
2. typical application scenarios
The CXSU63309 is particularly suitable for the following application areas:
· OLED and LCD Display Bias: Provide stable high-voltage power supply
· White LED backlight driver: Suitable for mobile phones, tablets, cameras and other equipment
· Portable Device Power ManagementSuch as PDA, digital camera, handheld instrument
· Boost conversion for battery-powered systems: Suitable for single-section lithium battery or double-section alkaline battery system
3. electrical characteristics and performance analysis
Under the conditions of input voltage of 3.7V and ambient temperature of 25 ℃, the main electrical parameters of the CXSU63309 are as follows:
· Feedback reference voltage: 1.25V (typical value), used to set the output voltage
· Switching current limit: 1.5A, provides reliable output protection
· Undervoltage Lockout Threshold: 2.2V (typical) with 100mV hysteresis
· Thermal shutdown temperature: 155 ℃
· enable control: High level> 1.5V on, low level <0.4V off
The efficiency curve shows that in the range of 10V output and load current of 50mA to 200mA, the efficiency remains above 85% under different input voltages, showing excellent performance.
4. functional architecture and working principle
CXSU63309 uses a fixed frequency peak current control architecture. At the beginning of each switching cycle, the internal MOSFET turns on and the inductor current rises. The current sense signal is amplified and compared to the error amplifier output, and the MOSFET is turned off when the two are equal. The system has good transient response and stability, and the built-in soft start circuit can limit the starting impulse current and avoid the output overshoot.
Under light load conditions, the chip automatically enters the pulse frequency modulation mode, which further reduces the switching loss and improves the light load efficiency.
5. Application Design Guide
1. Output voltage configuration
Connected to the FB pin through external divider resistors R1 and R2, the output voltage is determined by the following formula:
2. Suggestions for inductor selection
The recommended inductance value is 4.7 μH to 22 μH. A power inductor with low DC resistance, high saturation current and suitable for 1.2MHz frequency should be selected to improve efficiency and prevent magnetic saturation.
3. Input and output capacitance selection
It is recommended to use 1μF ceramic capacitors as input and output filters, preferably X5R or X7R materials. Its low ESR and good temperature characteristics help improve system stability.
4. Rectifier diode selection
Schottky diodes are recommended for their low forward voltage drop and fast recovery characteristics to improve overall efficiency. The reverse withstand voltage of the diode shall be higher than the output voltage, and the current capacity shall meet the following requirements:
5. PCB layout optimization recommendations
· Input and output capacitors should be close to the chip pins and well grounded
· The ground wire shall be wide and short and connected to the complete ground plane
· SW node wiring should be compact, reduce high frequency radiation
· The feedback network should be located away from the switch node and close to the FB pin
6. packaging and mechanical information
The CXSU63309 adopts standard SOT23-5 package, small size, suitable for high density mounting. The specific package size is detailed in the data manual, in line with industry standards, easy to mass production and automated assembly.
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Eight,About JTM-IC
JTM-IC (official website:jtm-ic.com) Committed to providing high-performance and high-reliability power management integrated circuit solutions for global customers. CXSU63309 are our high-efficiency boost converters for high-voltage drivers for portable devices, including display backlighting, bias power and battery-powered systems. We provide complete technical support, reference design and sample application services. Please visit our official website for more product details and application resources.
