In the field of high-voltage and high-current power supply, CXSD62684 is the first synchronous buck controller controlled by Pure Digital algorithm current mode. With 600V ultra-high input withstand voltage, 30A stable output current and software configurable protection mechanism, the power supply design of high-demand scenarios such as new energy vehicles and industrial robots is being subverted. Its original backflow prevention algorithm and multi-machine parallel current sharing technology provide engineers with unprecedented flexibility and reliability.
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[ CXSD62684 ]"
CXSD62684: revolutionary digital buck controller to unlock the smart future of industrial power supply
In the field of high voltage and high current power supply,CXSD62684As the first adoptionPure Digital algorithm current mode controlSynchronous buck controller600V ultra-high input withstand voltage,30A stable output currentAndSoftware configurable protection mechanism, is overturning the power supply design of high-demand scenarios such as new energy vehicles and industrial robots. Its original backflow prevention algorithm and multi-machine parallel current sharing technology provide engineers with unprecedented flexibility and reliability.
I. Three major technological breakthroughs define new industry standards
1. Digital algorithm current mode control
a. No external skew compensation is required: Original Digital kernel detects inductor current/voltage changes in real time
B .100kHz PWM dual-mode COT modulation: supports 0-100% duty cycle and improves efficiency by 12%
C.15seconds transient response: quickly respond to sudden load changes (3 times faster than traditional solutions)
2. Intelligent ecosystem protection
|
Protection type |
Technical Highlights |
Performance parameters |
|---|---|---|
|
Short circuit protection |
Pure algorithm control, no additional hardware |
Supports unlimited length and length |
|
Backflow prevention |
Real-time monitoring of inductor current direction |
Avoid output current recharge |
|
Temperature PID control |
Dual-Channel NTC sampling (TEMP1/TEMP2) |
± 1 ℃ accuracy, adjustable hysteresis |
|
Input Protection |
OVP/UVLO with hysteresis function |
Threshold software can be set |
3. Scalability revolution
a. Multi-machine parallel flow sharing: through droop coefficient RdroopAutomatic Balance current (save extra sampling circuit)
B. UART communication interface: 9600bps baud rate, supports real-time parameter configuration and fault diagnosis
c.LED intelligent indication: traffic light charging status class 7 fault code flashing (see Table 9-1 for details)
II. Landing guide for core application scenarios
1. New energy vehicle DC-DC converter (48-72v & rarr;12V/30A)Key points of design:
a. Drive circuit: PWM_H/PWM_L output dead TIME 100-500ns adjustable (Figure 8-8)
B. Current sampling: low-end MOS sampling scheme (Figure 8-3), cost reduction 40%
c. Inductance selection:
(Ripple current is calculated as 30%)
2. MPPT solar controllerAdvantages:
a. Light load power consumption <50MW (typical VDD quiescent current 30mA)
B. Temperature compensation PID automatic adjustment power point
c. Input undervoltage protection to prevent battery overdischarge
3. Industrial robot servo power supplyKey design:
a. Parallel current sharing: 3 modules parallel to achieve 90A output (Rdroop=0.05V/A)
B. Fault diagnosis: UART returns temperature/current data in real time (see Figure 10-2 for the protocol)
III. Golden rule of hardware design
1. Precision optimization of sampling circuit
|
Sampling type |
Circuit design formula |
Key points of layout |
|---|---|---|
|
Output voltage |
VOUT=Vout×R21/(R18 R21) |
C22 ≤ 10nF near pin |
|
Input voltage |
VIN=Vin×R22/(R17 R22) |
R22 ≤ 2 kΩ (example: 90V & rarr;2.62V) |
|
Temperature |
VTEMP=3.3V×NTC/(R24 NTC) |
B value 3950 thermistor |
2. Driver circuit design (Figure 8-8)
a. Bootstrap capacitor C5: 0.1 μF/25v recommended
B. Gate resistance R2/R6: calculated based on MOS tube Qg value (example: IRF3710 recommended 4.7 Ω)
c. Dead Time: 200ns typical value (configured by DT pin)
3. Communication interface application
a. Read and write parameters
# Read output voltage example (HEX small terminal mode)
CMD = 0x52# Read commands
ADDRESS = 0x2010# Vout register address
DATA = [0x04]# Read 4 bytes
B.Fault diagnosis:Active sending frame (CMD = 0 x53) contains over-temperature/over-voltage encoding
IV. Performance leap compared with traditional solutions
| Indicators | CXSD62684 | Traditional simulation scheme | Increase Range |
|---|---|---|---|
| Development cycle | Parameter software configuration (debugging assistant) | Hardware iteration | Shorten by 70% |
| Short circuit protection cost | Zero external device | Comparator logic circuit required | Cost reduction $0.3 |
| Light load efficiency (10% load) | 88% | 76% | + 12% |
| Average flow accuracy | ± 3% | ± 10% | 3 times higher |
V. Terminal Case: electric toy motorcycle DC-DC converter (Figure 6-1)
48-72v & rarr;12V/30A scheme measured data
1. Efficiency curve: full load 95%@ 72v & rarr; Light load 91%@ 5% Load
2. Temperature control:
a. Intelligent PID controls the temperature rise of MOS tube to ≤ 40 ℃ (Environment 25 ℃)
B. Over-temperature protection threshold 155 ℃ (delay 15 ℃)
3. Fault response:
a. Input undervoltage (<45V): turn off PWM within 3ms
B. Output Short Circuit: current limiting 30.5A ± 0.5A
VI. Application circuit design
1 power supply
CXSD62684 there are three power supplies, namely AVDD, VDDIO, and VDD. AVDD is the internal analog peripheral supply.
Electric power supply, recommended voltage value is 3.3V, recommended current value is greater than 0.1A,VDDIO is the internal digital circuit power supply, recommended
The voltage value is 3.3V. The recommended current value is greater than 0.1A. VDD is the internal 1.2V LDO output port. The recommended external capacitor setting is as follows:
The following figure shows 8-1.
2 output voltage sampling
The 21-pin VOUT of CXSD62684 is the output voltage sampling pin. The recommended peripheral circuit settings are shown in Figure 8-2 below.
R18 and R21 form a voltage dividing network. The resistance value is selected according to the highest output voltage. It is recommended that the voltage range of VOUT pin is
0.33V ~ 2.97V (note: 0.1 * VDD ~ 0.9 * VDD). For example, when the required output voltage is 12V, set R18 = 10kΩ,,R21
= 2 kΩ, calculated VVOUT = 12v/(R18 R21)* R21 = 2V, internal reference can be set in the debugging assistant.
C22 is used to filter out high-frequency switching ripple, and PCB layout is close to VOUT pin. In order to give consideration to filtering effect and sampling accuracy, push
Recommended: r21≤2 kΩ, c22≤10nf.
3 Current sampling
CXSD62684 20-pin CS is the current sampling pin, you can choose to sample MOS tube current or inductor current for design, push
Recommend low-cost low-end current sampling design. The peripheral circuit design is shown in Figure 8-3 below.
R7 is the low-end MOS tube current sampling resistor. When the output current I is 30A, select R7 = 1mΩ, mainly considering the dissipation power limit. In this example, PD= IOUT2* R7
= 0.9W, 2512/3W package is optional.
R12 and R14 are input resistors of operational amplifier. To ensure the symmetry of Differential sampling, R12 = R14 = 100Ω is recommended.
R13 and R15 partial voltage to obtain DC bias, select R13 = 10kΩ, R15 = 2kΩ, calculate DC bias
VBIAS = 3.3V/(R13 R15)* R15 = 0.55V.
R8 and R9 are the amplifier feedback resistance of the operational amplifier. Select R8 = R13, R9 = R15, and calculate the amplifier amplification AV =(R8 // R9)/R12 = 16.67.
To sum up, the output voltage V of the operational amplifierAMPO=VSENSE*AVVBIAS= 2.80V. So VCS=VAMPO= 2.80V, in line with the recommended CS feet
Voltage Range: 0.33V to 2.97V (note: 0.1 * VDD to 0.9 * VDD).
R19 and C20 form a low-pass filter to filter out high-frequency switching ripple. PCB layout is close to CS pin. In order to give consideration to filtering effect and sampling accuracy, it is recommended.
Select R19 ≤ 1kΩ and c20≤ 1nF.
4 input voltage sampling
The 17-pin VIN of CXSD62684 is the input voltage sampling pin. The recommended peripheral circuit settings are shown in the following figure 8-4.
R17 and R22 form a voltage dividing network. The resistance value is selected according to the highest input voltage. The recommended voltage range of VIN is 0.33V ~
2.97V (note: 0.1 * VDD ~ 0.9 * VDD). For example, if the required input voltage range is 50-90V, set R17 = 100kΩ,
R22 = 2 kΩ, calculated VIN=90V/(R17 Rlow) * R22 = 2.62V. The internal reference can be set in the debugging assistant.
C23 is used to filter high-frequency switching ripple, and PCB layout is close to VIN pin. It is recommended to give consideration to filtering effect and sampling accuracy.
Select r22≤2 kΩ and c23≤10nf.
5 Temperature sampling
The 15-pin TEMP1 and 13-pin TEMP2 of CXSD62684 are temperature sampling pins. The peripheral circuit settings are shown in the following figure 8-5.
R24 and NTC1 form a voltage dividing network, R24 = 10K, NTC1 select thermistor of the specification 10K/B value 3950, according to the supply
The voltage of TEMP1 is calculated based on the relationship between resistance and temperature provided by quotient. For example, when the sampling temperature of NTC1 is 25℃,
If the resistance value of the table is 10K, VTEMP1 = 3.3V/(R24 NTC1)* NTC1 = 1.65V. Calculation method of TEMP2 and TEMP1
The same is not described again.
C22 and C23 are the sampling signal filter capacitor, and the PCB layout is close to the corresponding pin.
6-drive 12V voltage sampling
The 16-pin VAUX of CXSD62684 is the driver 12V voltage sampling pin. The recommended peripheral circuit settings are shown in the following figure 8-6.
R23 and R26 form a voltage dividing network. The resistance value is selected according to the driving auxiliary voltage. It is recommended that the voltage range of the VAUX pin is
0.33V ~ 2.97V (note: 0.1 * VDD ~ 0.9 * VDD). For example, when the required driving voltage is 12V, set R23 = 10kΩ,,R26
= 2 kΩ, calculated VVAUX = 12v/(Rup Rlow)* Rlow = 2v.
C26 is used to filter out high-frequency switching ripple. PCB layout is close to VAUX pin. In order to give consideration to filtering effect and sampling accuracy, r26≤2 kΩ and c27≤10nf are recommended.
7 synchronous buck drive circuit
CXSD62684 14-pin PWM_H and 19-pin PWM_L are synchronous decompression band Dead zone complementary PWM output pins, typical input
The output waveform is shown in Figure 8-7. PWM_H is used to drive synchronous step-down high-end MOS tube, and PWM_L is used to drive synchronous step-down low
End MOS tube.
The external MOS tube half-bridge driver chip needs to be selected according to the actual application, mainly considering the parameters including withstand voltage and drive
The typical circuit design is shown in Figure 8-8 for output current capability, input and output logic, and whether there is undervoltage protection. PWM_H, PWM_L
The driver chip is connected to the HIN and LIN terminals through a resistor, and the I/O port protection resistor with a resistance of CXSD62684. C5 is Bootstrap
Capacity, D2 is a bootstrap diode, R2 and R6 are G-pole drive resistance, and the value is based on the drive current and MOS tube junction capacitance. Required
Add a quick shutdown circuit when necessary.
When the PCB is laid out, the resistor is close to the pin of CXSD62684, C5, C8, D2 are close to the driver chip, R2, R6 are close to the MOS tube.
8 LED indicator circuit
The 1-pin LED_A and 12-pin LED_ B of CXSD62684 are indicator pins. The recommended peripheral circuit settings are shown in the following figure 8-9.
LED lights can be used as charging indication and fault indication, charging indication is traffic light mode, D7 and D6 are selected as light emitting diodes,
R20 and R16 are current limiting resistors. The recommended current limiting value is ≤ 10mA.
Conclusion: a new era of software-defined power supply
CXSD62684 solves the triangle contradiction between efficiency, reliability and cost in high-voltage and high-current scenarios through digital kernel and algorithm innovation. Its programmable PID parameters (Kp /Ki /Kd), intelligent average flow and UART diagnostic capabilities are pushing industrial power into the "software defined" era. With the outbreak of the electric vehicle and energy storage market, the chip will become the preferred engine for 600V DC-DC design.
Development Support:
The official debugging assistant software supports open-loop test mode (PWM_H fixed 30% duty cycle) to accelerate hardware verification.
Technical Specification (product PDF)
For detailed PDF specifications, please contact us. You can also get free samples and technical support.!
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| Model | VCC starting voltage | VCC shutdown voltage | Input voltage range | Starting current | Switching frequency | Output voltage accuracy | Built-in power tube | Features | Encapsulation |
| CXDC65167 | 6.5V | 3.5V | 20-60V | Built-in quick start | 10-100K, peripheral can be set | 3% | Yes | 48v battery power supply system step-down switch power chip | ESOP8 |
| CXAC85204 | 16V | 9V | 20-150V | 3uA | Tiktok | 1.5% | Yes | Non-isolated system constant voltage stable output current | SOP7 |
| CXAC85207 | 9.5V | 7.8V | 10-25v | 80uA | 0-300K, peripheral adjustable | 1.50% | None | Programmable power supply chip | SOP16 |
| CXLB73135 | 9.5V | 7.8V | 10-25v | 80uA | 0-300K, peripheral adjustable | 1.50% | None | Programmable power supply chip | SSOP24 |
| CXDC65168 | 6.5V | 3.5V | 10-600V | 200uA | 0-300K, peripheral can be set | 1.5% | None | Synchronous rectification, high efficiency, can support constant current and constant voltage charging of battery | SOP16 |
| CXSU63303 | - | - | 7-150V | External Auxiliary power supply | 70k | 1.5% | None | Boost and Buck control chip, supporting high voltage and large current protection scheme | QFN32 |
| CXSU63304 | - | - | 13-90V | External Auxiliary power supply | 100K | 1.5% | None | Step-down digital power chip supporting PD3.0 protocol | QFN64 |
| CXSU63305 | 3.65V | 3.6V | 4-600V | 50uA | 0-300K, peripheral can be set | 1.5% | None | Boost synchronous rectification scheme, supporting high voltage and large current scheme | SOP16 |
| CXSD62669 | 16V | 9V | 20-90V | 3uA | Tiktok | 1.5% | Yes | Non-isolated system constant voltage stable output current | SOP7 |
| CXSD62670 | 16V | 9V | 20-600V | 3uA | Tiktok | 1.5% | Yes | Non-isolated system constant voltage stable output current | SOP7 |
| CXSD62671 | - | - | 10-115V | Built-in quick start | 140kHz | 3% | None | Short circuit hiccup, flexible and adjustable output voltage | ESOP8 |
| CXSD62672 | - | - | 10-115V | Built-in quick start | 120kHz | 3% | None | Short circuit lock, flexible and adjustable output voltage | ESOP8 |
| CXSD62673 | - | - | 10-100V | Built-in quick start | 120kHz | 3% | Yes | Zero power consumption enabled, flexible and adjustable output voltage | ESOP8 |
| CXSD62674 | - | - | 10-120V | Built-in quick start | 120kHz | 3% | Yes | Zero power consumption enabled, flexible and adjustable output voltage | ESOP8 |
| CXSD62675 | - | - | 10-120V | Built-in quick start | 120kHz | 3% | Yes | Short circuit hiccup, flexible and adjustable output voltage | ESOP8 |
| CXSD62676 | - | - | 10-120V | Built-in quick start | 120kHz | 3% | None | Short circuit hiccup, flexible and adjustable output voltage | ESOP8 |
| CXSD62677 | - | - | 10-120V | Built-in quick start | 70kHz | 3% | None | Short circuit lock, flexible and adjustable output voltage | ESOP8 |
| CXSD62678 | 4.6V | 3.8V | 4-600V | 50uA | 0-300K, peripheral can be set | 1.5% | None | Step-down synchronous rectification scheme, supporting high voltage and large current scheme | SOP16 |
| CXSD62679 | 16.5V | 8V | 10-600V | 200uA | 0-300K, peripheral can be set | 1.5% | None | Synchronous rectification, high efficiency, can support constant current and constant voltage charging of battery | SOP16 |
| CXSD62680 | 8.5V | 7.5V | 10-600V | 200uA | 0-300K, peripheral can be set | 1.5% | None | Synchronous rectification, high efficiency, can support constant current and constant voltage charging of battery | SOP16 |
| CXSD62681 | 9.5V | 7.8V | 11-250V | 200uA | 0-300K, peripheral can be set | 1.5% | None | Synchronous rectification, high efficiency, short circuit locking, built-in temperature protection, etc. | SSOP16 |
| CXSD62682 | 9.5V | 7.8V | 11-100V | 200uA | 0-300K, peripheral can be set | 1.5% | Yes | Synchronous rectification, high efficiency, short circuit locking, built-in temperature protection, etc. | QFN32 |
| CXSD62683 | 9.5V | 7.8V | 11-30V | 200uA | 0-300K, peripheral can be set | 1.5% | Yes | Synchronous rectification, high efficiency, short circuit locking, built-in temperature protection, etc. | QFN32 |
| CXSD62684 | - | - | - | External Auxiliary power supply | Maximum operating frequency 100kHz | - | None | Digital algorithm current mode synchronous buck control chip | SSOP24 |
| CXSD62685 | 9.5V | 7.8V | 10-25v | 80uA | 0-300K, peripheral adjustable | 1.50% | None | Synchronous rectifier step-down power supply control chip | SSOP16 |
