NCP1377BDR2G Symbol, Operating Principle, Technical Parameters and More
04 March 2024
Ⅱ. Symbol, footprint and pin configuration of NCP1377BDR2G
Ⅲ. Operating principle of NCP1377BDR2G
Ⅳ. Internal circuit architecture of NCP1377BDR2G
Ⅴ. Precautions for the use of NCP1377BDR2G
Ⅵ. Technical parameters of NCP1377BDR2G
Ⅶ. How does NCP1377BDR2G realize the protection function?
NCP1377BDR2G is a switching power supply controller chip with high efficiency and reliability. It can be used in various types of switching power supplies, such as AC-DC power supplies, DC-DC power supplies, battery chargers and LED drivers. In this article, we will provide you with the information of NCP1377BDR2G, including technical parameters, principle of operation and precautions for use, etc. with pin diagrams, and circuit architecture diagrams.
The NCP1377BDR2G is a controller that integrates a true current mode modulator and magnetization detector. This combination ensures full boundary or critical conduction mode under any load or line conditions, as well as minimal drain voltage switching (quasi-resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode once the power demand drops below a predetermined level. When this occurs at low peak currents, audible noise is eliminated.
For the NCP1377, an internal 8.0 us timer prevents the free-running frequency from exceeding 100 kHz, thus staying below the 150 kHz CISPR-22 EMI startup limit. The skip scaling feature allows the user to select how often burst retries occur. For the NC1377B, the internal timer duration is reduced to 3.0 us to enable operation at higher frequencies up to 300 kHz. Transformer core reset detection is achieved through the auxiliary winding, which also facilitates fast overvoltage protection (OVP). Once OVP is detected, the IC is permanently latched. The 1377 has a sampling time of 4.5 milliseconds, while the B version has a sampling time of 1.5 milliseconds.
The NCP1377 also features highly efficient protection circuitry that disables the output pulses and enters a safe burst mode to attempt a restart in the event of an overcurrent condition. The device automatically recovers once the overcurrent condition ceases. Finally, an internal 1.0 millisecond soft-start eliminates traditional cranking stress.
Alternatives and equivalents:
• NCP1342AMDCCDR2G
The following figures show the symbol, footprint and pin configuration of NCP1377BDR2G respectively.
It has eight pins and its name and description are as follows:
Pin 1 (Demag): The auxiliary FLYBACK signal ensures discontinuous operation and offers a fixed overvoltage detection level of 7.2V.
Pin 2 (FB): By connecting an optocoupler to this pin, the peak current setpoint is adjusted accordingly to the output power demand. By bringing this pin below the internal skip level, you shut off the device.
Pin 3 (CS): This pin senses the primary current and routes it to the internal comparator via an L.E.B. By inserting a resistor in series with the pin, you control the level at which the skip operation takes place.
Pin 4 (GND): -
Pin 5 (Drv): The driver’s output to an external MOSFET.
Pin 6 (Vcc): This pin is connected to an external bulk capacitor of typically 10 μF.
Pin 7 (NC): This unconnected pin ensures adequate creepage distance.
Pin 8 (HV): Connected to the high-voltage rail, this pin injects a constant current into the Vcc bulk capacitor and ensures a clean lossless startup sequence.
The NCP1377BDR2G adopts three operating modes, including constant frequency PWM mode, pulse frequency modulation PFC mode and hybrid mode. In constant frequency PWM mode, the chip regulates the output voltage by controlling the switching time of the switching tubes, thus realizing the stability and reliability of the power supply. In pulse frequency modulation PFC mode, the chip realizes power factor correction by controlling the switching frequency of the switching tubes, which can improve the efficiency of the power supply. In hybrid mode, the chip uses both constant frequency PWM mode and pulse frequency modulated PFC mode to achieve higher efficiency and better stability.
When using NCP1377BDR2G, we should pay attention to the following aspects:
1. Thermal management: We have to ensure that the operating temperature of NCP1377BDR2G is within the safe range to avoid overheating causing performance degradation or damage to the chip. When designing and laying out the PCB board, we must carefully consider the location of the heat sink and the ventilation holes to ensure that the chip can get effective heat dissipation.
2. Input and output port protection: We should add appropriate protection circuits to the input and output ports. These protection circuits should be equipped with functions such as over-voltage protection and over-current protection to prevent NCP1377BDR2G and peripheral components from being damaged due to excessive voltage or current.
3. PCB layout design: A well-designed PCB layout is the key to ensure the stability and anti-interference capability of the NCP1377BDR2G system. We should avoid mutual interference between high-frequency circuits and low-frequency circuits, maintain signal integrity, minimize the loop area, and reduce electromagnetic radiation and interference from sensitive components.
4. Circuit testing and debugging: During circuit testing and debugging, we need to ensure that we use appropriate test equipment and methods to find and solve problems in a timely manner. Based on the test results, we will adjust and optimize the circuit of NCP1377BDR2G to ensure that the performance indicators such as output voltage, current and efficiency meet the design requirements.
5. Peripheral component selection: We should select appropriate peripheral components for NCP1377BDR2G, including capacitors, inductors, diodes, etc., to ensure the stability and performance of the circuit. In addition, we should also pay attention to the parameter matching of the peripheral components and the compatibility of the operating frequency to avoid affecting the efficiency and EMI performance of the system.
6. Operating conditions and parameter ranges: In order to ensure the normal operation of the NCP1377BDR2G chip, we must ensure that all operating conditions and parameters, such as operating temperature, output voltage and current, and input voltage, etc., are in accordance with their specifications. In addition, we must always be vigilant to avoid any parameter exceeding its maximum rating, thus preventing damage to the chip or affecting system stability.
• The manufacturer of NCP1377BDR2G is onsemi.
• Its switching frequency is 300kHz.
• Its input voltage is 11V and output voltage is 18V.
• Its output current is 500 mA.
• It has a rise time of 40 nanoseconds and a fall time of 20 ns.
• Its power supply voltage is 7.5V to 18V.
• Its installation method is SMD or SMT.
• The operating temperature of NCP1377BDR2G is -25°C to 125°C.
• NCP1377BDR2G belongs to the category of switching controllers.
• NCP1377BDR2G has a length of 5 mm, a width of 4 mm, and a height of 1.5 mm.
• NCP1377BDR2G has 8 pins and comes in SOIC-8 package and cut tape (CT) packaging.
First of all, it has the functions of overload protection, overheat protection, undervoltage protection and short circuit protection. When the chip detects these abnormal conditions, it will take appropriate measures to protect the stability and reliability of the power supply system.
Second, the NCP1377BDR2G also has an internal skip cycle function. When the power requirement drops to a pre-determined level, the controller can immediately enter burst mode, thus avoiding noise at low peak currents. This feature allows the power supply system to run more smoothly and reduce potential disturbances.
In addition, the NCP1377BDR2G features effective protection circuitry. If an overcurrent condition occurs, the chip disables the output pulse, enters a safe burst mode, and attempts to reboot. Once the fault is cleared, the device automatically recovers, thus ensuring continuous stable operation of the power system.
Finally, the NCP1377BDR2G also features transformer core reset detection. Through the use of an auxiliary winding implemented on a dedicated pin, the chip is able to detect and implement fast overvoltage protection (OVP). Once OVP is detected, the IC permanently latches shutdown to protect the power system from damage.
Frequently Asked Questions
1. What is the replacement and equivalent of NCP1377BDR2G?
You can replace the NCP1377BDR2G with NCP1342AMDCCDR2G, NCP1377BDR2, NCP1377DR2G or UCC28600DR.
2. What is the function of NCP1377BDR2G?
NCP1377BDR2G is used to control and regulate the output voltage of power supplies by modulating the width of pulses in the output waveform.
3. What are some advantages of using NCP1377BDR2G in power supply designs?
Some advantages include its high voltage startup capability, built-in protection features, wide input voltage range, and automatic burst mode operation for improved efficiency in light load conditions.
