Datasheet AP3917D (Diodes) - 6
| 制造商 | Diodes |
| 描述 | 700V Non-isolated regulator up to 370mA output current in SO-7 package |
| 页数 / 页 | 12 / 6 — AP3917D. Performance Characteristics. Overall Introduction. VBP Waveform … |
| 文件格式/大小 | PDF / 593 Kb |
| 文件语言 | 英语 |
AP3917D. Performance Characteristics. Overall Introduction. VBP Waveform and ON/OFF Control. RESTART. Auxiliary VBP Supply
该数据表的模型线
文件文字版本
AP3917D Performance Characteristics
(continued)
Overall Introduction
The AP3917D is a universal AC input step-down power switcher. Peak current and switching frequency reduce as the load decreases, thus device receives excellent efficiency performance at light load and improving the overall system efficiency. Coordinating with an external single-winding inductor can achieve a low BOM cost solution.
VBP Waveform and ON/OFF Control
The AP3917D control circuit power supply voltage VBP is charged by the internal high-voltage regulator. When the BP voltage charges to VBP_HVOFF (8.5V), the IC starts up, and the internal high-voltage regulator is turned off. When the BP voltage drops below VBP_HVON (8.2V), the internal high-voltage regulator turns on again to charge the external BP capacitor. When fault conditions happen, such as overload faults, short-circuit faults, over-temperature faults, and open-loop faults, the AP3917D stops switching. Afterwards, an internal current source IBP_LATCH discharges the external BP capacitor. The internal high-voltage regulator will not turn on again until the voltage on the BP capacitor drops below VBP_RESTART (4.5V). The restart time interval is proportional to the capacitance of external BP capacitor: the larger capacitance of the external BP capacitor, the longer the restart time. The restart time after a fault is about V − V V − V t = C ( BP _ FAULT BP _ RESTART BP _ HVOFF BP _ RESTART + ) RESTART BP I I BP _ LATCH HV Where: • V is actual voltage value of BP pin at the time of fault, which is between V and V BP _ FAULT BP _ HVON BP _ HVOFF Figure 1 shows the typical waveform of VBP. VBP_FAULT VBP_HVOFF=8.5V VBP VBP_HVON=8.2V V
BP
_
RESTART
=4.5V ON ON ON ON HV REGULATOR OFF OFF OFF Figure 1. VBP Waveform and HV Regulator ON/OFF Status
Auxiliary VBP Supply
If the output voltage is higher than the voltage of VBP_HVON, an auxiliary VBP supply can be implemented to reduce overall power consumption by connecting a resistor (R5) between C4 and C5. A standby power of less than 30mW can be achieved especially in a no-load condition. Figure 2 shows the low standby power circuit with the auxiliary VBP supply. R5 R1 D2 C4 DB1 L1 C5 R2 R3 C6 L2 F1 BP S +V L FB S N C1 C2 NC D 1 C 3 R4 Drain NC U1 AP3917D GND Figure 2. Low Standby Power Circuit with Auxiliary VBP Supply AP3917D 6 of 12 March 2025 Document number: DS41540 Rev. 8 - 3
www.diodes.com
© 2025 Copyright Diodes Incorporated. All Rights Reserved.
(continued)
Overall Introduction
The AP3917D is a universal AC input step-down power switcher. Peak current and switching frequency reduce as the load decreases, thus device receives excellent efficiency performance at light load and improving the overall system efficiency. Coordinating with an external single-winding inductor can achieve a low BOM cost solution.
VBP Waveform and ON/OFF Control
The AP3917D control circuit power supply voltage VBP is charged by the internal high-voltage regulator. When the BP voltage charges to VBP_HVOFF (8.5V), the IC starts up, and the internal high-voltage regulator is turned off. When the BP voltage drops below VBP_HVON (8.2V), the internal high-voltage regulator turns on again to charge the external BP capacitor. When fault conditions happen, such as overload faults, short-circuit faults, over-temperature faults, and open-loop faults, the AP3917D stops switching. Afterwards, an internal current source IBP_LATCH discharges the external BP capacitor. The internal high-voltage regulator will not turn on again until the voltage on the BP capacitor drops below VBP_RESTART (4.5V). The restart time interval is proportional to the capacitance of external BP capacitor: the larger capacitance of the external BP capacitor, the longer the restart time. The restart time after a fault is about V − V V − V t = C ( BP _ FAULT BP _ RESTART BP _ HVOFF BP _ RESTART + ) RESTART BP I I BP _ LATCH HV Where: • V is actual voltage value of BP pin at the time of fault, which is between V and V BP _ FAULT BP _ HVON BP _ HVOFF Figure 1 shows the typical waveform of VBP. VBP_FAULT VBP_HVOFF=8.5V VBP VBP_HVON=8.2V V
BP
_
RESTART
=4.5V ON ON ON ON HV REGULATOR OFF OFF OFF Figure 1. VBP Waveform and HV Regulator ON/OFF Status
Auxiliary VBP Supply
If the output voltage is higher than the voltage of VBP_HVON, an auxiliary VBP supply can be implemented to reduce overall power consumption by connecting a resistor (R5) between C4 and C5. A standby power of less than 30mW can be achieved especially in a no-load condition. Figure 2 shows the low standby power circuit with the auxiliary VBP supply. R5 R1 D2 C4 DB1 L1 C5 R2 R3 C6 L2 F1 BP S +V L FB S N C1 C2 NC D 1 C 3 R4 Drain NC U1 AP3917D GND Figure 2. Low Standby Power Circuit with Auxiliary VBP Supply AP3917D 6 of 12 March 2025 Document number: DS41540 Rev. 8 - 3
www.diodes.com
© 2025 Copyright Diodes Incorporated. All Rights Reserved.