Overview
The NCP1253ASN65T1G is a highly integrated current-mode PWM controller designed by ON Semiconductor for offline power supplies. This component is housed in a compact TSOP-6 package and is capable of delivering high performance and ruggedness. It operates at a fixed switching frequency of 65 kHz and features advanced protection mechanisms, low startup current, and efficient power management.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| Switching Frequency | kHz | 61 | 65 | 71 |
| Supply Voltage Range | V | - | - | 28 |
| Maximum Duty Cycle | % | 76 | 80 | 84 |
| Start-up Current | μA | - | - | 15 |
| Internal Current Setpoint | mV | - | 0.8 | - |
| Propagation Delay from Current Detection to Gate Off-state | ns | 100 | 150 | - |
| Leading Edge Blanking Duration | ns | - | 300 | - |
| Internal Soft-start Duration | ms | - | 4 | - |
Key Features
- Current-mode Operation with Internal Ramp Compensation: The NCP1253 operates in peak current mode control at a fixed frequency, allowing for easy compensation of subharmonic oscillations through a simple resistor in series with the current-sense information.
- Low Startup Current: The controller draws less than 15 μA during startup, facilitating the design of low standby power adapters.
- EMI Jittering: An internal low-frequency modulation signal helps in spreading out energy in conducted noise analysis, improving the EMI signature.
- Frequency Foldback Capability: The controller reduces switching frequency to a minimum level of 26 kHz during light-load conditions to minimize standby power.
- Short-circuit Protection: The controller features auto-recovery or latched protection modes depending on the version, ensuring robust operation during fault conditions.
- VCC Overvoltage Protection (OVP): The controller monitors the VCC level and latches off if the voltage exceeds a set threshold, protecting the IC from fault conditions.
Applications
- AC-DC converters for TVs, set-top boxes, and printers.
- Offline adapters for notebooks and netbooks.
- Low-cost AC-DC adapters and open-frame power supplies.
Q & A
- What is the switching frequency of the NCP1253ASN65T1G? The switching frequency is 65 kHz.
- What is the maximum supply voltage range for the NCP1253? The maximum supply voltage range is up to 28 V.
- How does the NCP1253 manage EMI? The NCP1253 uses internal low-frequency modulation to improve the EMI signature.
- What is the start-up current of the NCP1253? The start-up current is less than 15 μA.
- Does the NCP1253 have short-circuit protection? Yes, it features auto-recovery or latched protection modes depending on the version.
- What is the purpose of the VCC OVP in the NCP1253? The VCC OVP monitors the VCC level and latches off the controller if the voltage exceeds a set threshold.
- What are the typical applications of the NCP1253? Typical applications include AC-DC converters for TVs, set-top boxes, and printers, as well as offline adapters for notebooks and netbooks.
- How does the frequency foldback capability work in the NCP1253? The controller reduces the switching frequency to a minimum level of 26 kHz during light-load conditions to minimize standby power.
- What is the package type of the NCP1253ASN65T1G? The package type is TSOP-6 (Pb-Free).
- Is the NCP1253 suitable for low-cost power supply designs? Yes, it is particularly suited for low-cost AC-DC adapters and open-frame power supplies due to its low part count and cost-effectiveness.
