ECRI Microelectronics

FAQs

How do I stay informed about new product releases?
ECRIM has a dedicated space on our website highlighting all press releases, which details new product announcements and company news.
Can I buy ECRIM s products directly from ECRIM?
Many customers prefer to buy directly with ECRIM. ECRIM's automated and flexible factory achieves lead times is typical in the industry allowing many customers to ECRIM's Order Acquisition group at by phone: +86 551 63667943 or e-mail: sales@ecrim.cn. 
What are the current lead-times on your products?
ECRIM maintains consistent lead times of stock for 15 weeks.
Please contact ECRIM for the updated availability of items from stock.
What are the terms and conditions of sale for your products?
ECRIM's Terms and Conditions
How do I handle returns for ECRIM product?
If you wish to return the product due to a technical failure, please contact our technical support group.
If you wish to return product for reasons other than technical performance issues, please contact our customer support group at ECRIM by phone: +86 551 63667943 or e-mail: sales@ecrim.cn
Where do I request products if I do not see them on your website?
All of ECRIM's standard product data sheets can be found on our website. You can access them through the  "Products" links at on the Home page of the ECRIM  Web Site. However, if you have requirements for a custom or modified standard product or wish to inquire about possible future product releases, please contact an ECRI Mr sales Tel: +86 551 63667943 person directly.
Do you make custom power supply products?
ECRIM offers a broad line of standard DC-DC converters to cover a wide range of power requirements and applications. However, customers often have special requirements that are not covered with a standard product. This may include a specific package size, input/output voltage, power level or a special feature. ECRIM will consider all requests for modified and custom power supplies. In addition, ECRIM will consider providing system level products as well. To discuss your individual requirements, contact the ECRIM sales group Tel +86 551 63667943.
What is Pulse Width Modulation-PWM?
Pulse width modulation is a modulation control method commonly used in switching power supplies. Its characteristic is keeping the switching frequency constant, namely not changing the switching cycle but change the pulse width, which makes the change of the output voltage of the switching power supply least when the voltage and load of the electrical network change.
What is Duty Cycle Ratio?
The duty cycle ratio refers to the proportion of transistor conduction time toN in a period T. The  duty cycle ratio D=toN/T.
What is Hard Switching?
When the voltage or current on the transistor has not yet been zero, the switch tube is forced to turn on or off. At this time, the switch tube voltage drops or rises and the current rises or falls with an overlapping process. Therefore, the tube has a loss during the switching. This way of switching is Hard Switching.
What is Soft Switching?
The transistor switch is turned on when its voltage is zero, or it is turned off when the current is zero, so that the tube loss is close to zero during the switching process. This switching mode is called soft switching.
What is Resonance?
Resonance is a physical phenomenon in AC circuits. In the ideal (no parasitic resistance) inductance and capacitance series circuit input, plus a sinusoidal voltage source, when the frequency of the power supply is a certain frequency, the capacitive reactance is equal to the inductive reactance, the circuit impedance is zero, and the current can reach infinity. The phenomenon is called series resonance. Similarly, when an ideal LC parallel circuit adds a sinusoidal current source, the total admittance of the circuit is zero, and the voltage on the element is infinite, which is called parallel resonance.
What is Quasi-Resonance?
For a LC series circuit with a switch, when the current oscillates at the resonant frequency, if the switch acts, the current sinusoidal oscillation occurs only in part time of one cycle, and the current assumes a quasi-sinusoidal, a phenomenon known as quasi-resonance. Similarly, in an LC parallel circuit, quasi-resonance can also be obtained by means of a switching action.
What is zero voltage switching?
Using the resonance phenomenon, when the device voltage oscillates to zero according to a sine law in the switching converter, the device is turned on, which is called zero voltage switching.
What is zero-current switching?
When the device current of the switching converter oscillates to zero according to a sine law, the device is turned off, which is called zero-current switching.
What is PWM switching converter?
The PWM switching converter refers to a switching converter that controls the switching of the transistors through pulse width modulation. It belongs to the constant-frequency controlled hard switch type.
What is off-line switching converter?
The off-line switching converter is an AC/DC converter whose input rectifier and flat-wave capacitor are directly connected to the AC network.
What is resonant converter?
Using the resonance phenomenon, the voltage or current on the device in the switching converter is changed in a sinusoidal manner, thereby creating a condition of ZVS or ZCS, called a resonant converter. Split two series and parallel resonant converters. Connect the LC network in series at the output end of the bridge converter bridge, and then connect the transformer and rectifier to obtain a series resonant DC/DC converter; connect the load (including transformer and rectifier) in parallel across the capacitor of the series LC network of the bridge converter. , available DC/DC parallel resonant converter.
What is quasi-resonant converter?
Using the quasi-resonant phenomenon, the voltage or current on the device in the switching converter is changed by a quasi-sinusoidal law, thus creating a condition of ZVS or ZCS, which is called a quasi-resonant converter. In a single-ended, half-bridge or full-bridge converter, a quasi-resonant converter can be obtained using parasitic inductance and capacitance or externally coupled resonant inductance and capacitance. The resonance parameters can be more than two, for example three or more, which is also referred to as a multi-resonant converter. In order to keep the output voltage almost constant, both the resonant and quasi-resonant converters must use variable frequency control.
What is the use of a transformer in a DC DC converter circuit?
There are three main roles:
1) Power transfer: The transformer transfers the input side energy to the output side.
2) Voltage conversion: By setting the transformer turns ratio, the given input voltage is converted into the required output voltage.
3) Insulation isolation: Insulation isolation between the input side circuit and the output side circuit.
Why are MOSFETs mostly preferred than IGBTs in DC DC converters?
The design of DC DC converter generally requires small size and high operating frequency. Compared with IGBTs, MOSFETs have the characteristics of small size and high switching frequency (up to several hundred KHZ ~ several MHZ), so they are preferred in DC DC design. Use MOSFETs as power switches. At the same time, MOSFETs are mainly used in several watts to hundreds of watts, and IGBTs are mainly used in several hundred watts to several kW.
What is Zero-Switching Converter?
In the quasi-resonant converter, an auxiliary switch is added to control the operation of the resonant network to make the converter work for a part of the time according to the ZCS or ZVS quasi-resonant converter, and the other part of the time is operated by the PWM converter, called ZCS- PWM or ZVS-PWM converter. It combines the features of ZCS (or ZVS) soft switching and PWM constant frequency control. The inductance in the resonant network is then in series with the main switch.
What is Zero-Transition Converter?
If the resonant network is connected in parallel with the main switch and still controlled by the auxiliary switch, the same characteristics as the ZCS-PWM or ZVS-PWM converter can be obtained, which are respectively called ZCS-PWM or ZVS-PWM converter. It is essentially still a ZCS or ZVS soft-switch-PWM converter.
What is Phase-Shift FB ZVS-PWM Converter?
In a full-bridge switching converter, a resonant and phase-shifted full-bridge ZVS-Pwm converter utilizing a switching junction capacitance and a transformer leakage inductance (plus a resonant element if necessary) is utilized. It is also a soft-switching-PWM converter for high power, low voltage output.
What is continueous conducting mode?
Continuous conduction mode means that the inductor current (or the capacitance voltage of the transmitted energy) is always greater than zero during the period.
What is single-ended converter?
The most simple circuit type DC DC converter with isolation transformer is characterized in that the core of the high-frequency transformer is excited by the unidirectional pulsating current, and the magnetic flux in the core changes only on the hysteresis loop in one cycle, so the magnetic properties of the core Can you make full use of it? According to the excitation direction in a week, there are forward and flyback converters. There are also Cuk converters with isolation. There can be multiple outputs.
What is Forward Converter?
The single-tube forward converter is a simple-ended single-ended converter, which is essentially a Buck converter with an isolation transformer. The secondary side output terminal is connected with a freewheeling diode in addition to a diode in series. The characteristic is that when the switch tube is turned on, the energy is transmitted from the primary side to the secondary side; when the switch tube is turned off, the secondary side relies on the inductor to continue to flow. However, in both cases, the core is subjected to the same excitation direction. Therefore, a "reset" action must be taken to return the flux to the original position at the beginning of the cycle at the end of the cycle. The single-tube forward converter is suitable for low power, and the voltage of the switch tube is calculated according to 2Vi. Vi is the input voltage.
What is Two-transistor forward converter?
In the forward converter, two switching tubes are connected in series with the primary winding of the transformer, and are turned on or off at the same time. The primary side of the transformer is connected like a bridge, and the opposite sides of the bridge arm are two switching tubes and two diodes. The output of the bridge is connected to the primary side of the transformer, and the secondary side circuit is the same as the single-tube forward. Its operating mode is completely different from that of a bridge converter. Since the demagnetization current passes through the diode and the primary winding during Toff, there is no need to separately provide a demagnetization winding. The two-switch forward converter can be used for medium power, and each tube is subjected to a voltage of approximately Vi. Two sets of identical double-switch forward converters are connected in parallel, and the input is connected in series or in parallel. After being connected to the AC/DC rectifier, it can be used for high-power output and input terminal to the rectified output of AC400V or 220 grid.
What is Flyback Converter?
The flyback converter is one of the simplest single-ended converters. Unlike the forward circuit, the secondary side of the transformer is connected to the reverse diode. In the Toff, the magnetic current flows in the secondary winding of the transformer, and there is no need to separately provide a demagnetizing winding. The flyback converter is essentially an isolated Buck-Boost converter, and its transformer acts as a transmitting energy element. Therefore, the transformer core should have a large air gap, making the magnetic performance utilization less. It is suitable for low power. The switch tube is subjected to the same voltage as the single-switch forward circuit.
What is Push-Pull Converter?
The two symmetric forward circuits are connected in a push-pull form to form a square wave inverter. The power transformer is connected to the push-pull rectifier and the LC filter circuit to form a Buck-type push-pull converter, but the output does not require an additional freewheeling diode. The main advantage is that the design is simple, the transformer core is fully utilized, and no additional magnetic winding is required. Each tube withstands voltage greater than 2Vi. The disadvantage is that the two tubes may be electrically conductive at the same time. Can be used for medium power and when multiple outputs are required. When the inductor is connected to the input, it is called a Boost push-pull converter.