Common problems

General issues

Power Integrations provide digital gate driver?

Power Integrations gate drive using the digital and analog technology at the same time.Each Power Integrations in the drive highly integration SCALE and SCALE - 2 the chipset of mixed signal structure has been adopted.Strategically we utilize the advantages of digital module and simulation unit, in order to maximize performance.

For example, in taking into account all factors such as operating conditions, the voltage fluctuation and component aging, digital launch control than analog control more precise.In addition, through the adoption of digital filter and digital timing management can bring a lot of chip area and the corresponding cost savings.

If we look at IGBT short circuit protection, the situation will be very different.Analog signal processing speed is faster than any inherent low cost of digital simulation, which needs to wait for the next few clock cycles to respond to the request.

Another can support analog circuit, through active clamp, dv/dt and di/dt control feedback to the management of switch characteristic of IGBT.These functions are digital programming can naturally reduce the production cost of the drive.However, this kind of vulgar "number" the adjustment of the IGBT module, and switch to achieve the best performance (need to adopt the high cost of power module) and too much fine-tuning compared to many more.

Usually exists the question: how would you like to pay for digital IGBT drive the performance of the compromise between the cost and Numbers - and in doing so, if there are any more benefits.
IGBT or MOSFET power switch must always be regarded as a simulator can give full play to its performance advantage.So the best drive will be digital domain and simulating the actual joint of "reality".
Power Integrations that simulation combined with the integration of digital function can be the most optimal cost-effective give full play to their respective advantages in the field of the two.

whyPower IntegrationsThe drive is not under short circuit conditions slowly shut off?

Named after the drive circuit in different ways, such as "two level off", "soft shut off", "slow shut off") are in normal operation mode using low resistance to shut off the IGBT gate resistance, in order to reduce the switching loss, and when the situation is in short circuit or over current is detected using high resistance values (or low gate current).However, the problem is that must be reliably detected the following situations: Vce monitoring delay phenomenon always exists (in this case, called response time), the delay must disappear before failure is detected.The time value is usually up to 10 us.If the short circuit is real, and IGBT pulse is less than the response time for driver, not a failure is detected, the circuit will be shut off very quickly.IGBT is then destroyed because of the overpressure.In addition, the coverage of limiting case (between over-current/without current) will also be a problem.

Normally, such a circuit must be considered as dangerous, and therefore cannot be used to Power Integrations.

Power Integrations suggest should be installed with minimum inductance value of element and set the worst case of Power component, namely, should choose gate resistance, so that each time the shutoff and under maximum intermediate dc bus voltage across for safety control flow and short circuit.
For high Power application, Power Integrations have developed have (advanced) active clamping function SCALE and SCALE - 2 plug and play device series.These products represent the ratio has introduced "slow shut off" method is more complex, but a better and more reliable solution.

The use of the drive and size set

Power semiconductor the gate charge specified in the data sheet can be used to set the size of the drive?

Drive performance is usually calculated according to the following formula:
P = FSW * * dVge Qc
FSW: switching frequency
Qc: gate charge
DVge: gate voltage swing

Gate charge depends largely on the gate voltage swing.Therefore, you must check what kind of gate voltage swing it applies.Usually, SCALE drives gate voltage swing to 30 v (15 v to + 15 v), SCALE - 2 drives gate voltage swing to 25 v (- 10 v to + 15 v) or 23 v (8 v to + 15 v).

If specified in the data sheet of the gate charge is applicable to different gate voltage swing (such as 0 v...+ 15 v Mitsubishi ™, 15 + 15 v/v Infineon ™, - 5 v / + 15 v Semikron ™), the actual gate charge can charge by the curve (if provided in the data sheet) to determine, or can be combined with the actual gate current measurement using a digital oscilloscope.
Please refer to the application guide the AN - 1001.

CONCEPTA driver forIGBT/MOSFETModules provide short circuit protection?CONCEPTDrive to see if they offerVce /Refund saturation detection?

All CONCEPT drive contains a Vce detector, can be used to measure power device after conduction voltage IGBT or MOSFET.If power components suffer from too much current (significantly higher than the power switch is two times the rated current or short circuit problem, collector and emitter (drain to source voltage will be increased accordingly.This relationship as a function of voltage and current will be rising Vce detector is detected, which can effectively protect the power component.

Vce detection, however, cannot provide reliable to load short circuit and over-current protection.This is because still allow for IGBT over-current levels may already be close to the connected motor or similar load limit value.In addition, only return a saturation effect can lead to IGBT collector emitter voltage rose sharply.If the current is still below saturation threshold, back real short circuit will not happen.

Usually, Vce testing should be regarded as the protection of power device, in practice, should be through a dedicated load current measurement and adjustment, or other appropriate measures to provide effective load protection.Please refer to the application guide the AN - 1101.

CONCEPTDrives have anti-overloading function?

Most CONCEPT drives don't limit the input current, so don't limit module power output of the driver.This means that they are not on the output side permanently to provide short circuit protection.The advantage of this design is that the drive can experience a short overload.Their corresponding data sheet shows the restrictions of this model.

Typical examples of application are high frequency switch phase alternating with appropriate pause when sudden pulse operation mode.Another instance represented by pulse power topology, the topological also requires very high peak load, but significantly lower average power consumption.

The advantage of this special operation mode already embodied in the CONCEPT of products, not only saves the hard drive in the general short circuit protection, can also be flexible configuration of input load limit.

Thermal management shows,Some of the drive element temperature more than85 ° c.(For example,,To achieve95 ° c.).If this situation is allowed?There is a thermal overload or drive?

Usually, the CONCEPT design of the drive maximum temperature to + 85 ° C (please refer to the corresponding data sheet).Drive components after absorbing energy makes its temperature rose above ambient temperature.Therefore, when the temperature more than the environment temperature of some components, this is a relatively normal thing.At this point, the driver would not necessarily appear overload.

Whether to allow short high-frequency sudden impulse drive more than plug and play the maximum switching frequency specified in the data sheet?

Gate drive and plug and play drives the maximum continuous or average switching frequency is first and foremost by elements as a result of the average load of temperature to decide.Given the element exists transient thermal impedance, briefly appeared high switch frequency is allowed.
Due to the thermal time constant is bigger, can assume that in less than 1 millisecond abrupt pulse duration and the highest 0.1 within the duty ratio of repeated use of the average power loss, namely abrupt pulse is about 10 times the average switching frequency of the is allowed.
If it means more than the absolute maximum rating specified in the data sheet, please contact the CONCEPT support team for further instructions.

Circuit topology

CONCEPT drives can be used for IGBT series application directly?

In general, support the application of multilevel CONCEPT can be used to drive IGBT series circuit.But should pay attention to the following: even if it can synchronously driven IGBT series, but because of the IGBT parameter differences itself, symmetric partial pressure and limited pressure only through other measures (such as dv/dt and active clamping or buffer circuit).Another problem is that the drive power supply must have a high dielectric strength.

CONCEPT can be used to drive the multilevel converter?

In general, the current drive CONCEPT plug and play support multilevel topology;Please see the relevant document of drives.
In multilevel mode, the driver can confirm what happened any failure, but will not automatically shut off.The optimal cut-off timing of each IGBT control circuit to determine by the user.

CONCEPT can drive in the case of short circuit to provide safety protection for multilevel converter?

In the multilevel converter, must make the order to maintain a specific switching devices.For example,,for于三电平拓扑，在短路情况下，必须先关外管再关内管。否则，内管可能因严重过压而受损/毁坏。对正确开关时序的控制由微控制器来完成。为实现此控制时序，不允许驱动器在检测到短路后自行关断功率开关。驱动器只能“通知”微控制器。CONCEPT的驱动器可以满足这一要求。CONCEPT驱动器有一种称为“高级有源钳位”的功能，它允许驱动器能够在检测到短路后直接关断功率器件。

I am in a matrix converter (quasi resonant converter) using the nuclear CONCEPT drive.whyRefund saturation detection电路（短路保护）会在非短路情况下有规律地触发呢？

Because in such a converter topology, there had been no current flows through the conduction of power semiconductor initially, then through the high di/dt current, therefore in the semiconductor short-time dynamic positive overvoltage.If the over voltage over the back of the drive saturation threshold, is to go back saturated detector is likely to trigger.

Can be improved by adjusting the resistance Rth this problem solved the threshold.Check and ensure the response time can't more than the use of power semiconductor allow maximum short circuit duration.And also recommended in these applications, the use of a resistor string to replace the Vce detection circuit of high voltage diodes, to avoid misoperation.Please refer to the application guide the AN - 1101.

Connect the gate driver

Plug and play drives for electrical interfaces,It is recommended to use what kind of cable?

CONCEPT is recommended to use twisted-pair cable ribbon cable (such as 3 m ™ 1700/20 or 2100/20 cable) door drive connected to the controller level.

forCONCEPTGate drive is there a required input and output signals?

According to specific application conditions, it is suggested that the gate drive input (INA, INB input) and/or output (SO1, SO2 output) loop to add specific components - especially between the drive and the controller level long bridge.For more information, please refer to the application guide the AN - 1101.

adviceCONCEPTHow much was used toPWMSignal voltage level?

CONCEPT drive is suitable for use 3.3 V to 15 V logic level of the PWM signal.According to the specific conditions of application of recommended different voltage level.For example,,如果门极驱动器和控制器位于同一个PCB，而且只相隔数厘米，那么3.3V或5V逻辑电平是可行的。在具有高噪声水平和/或使用电缆连接驱动器和控制器级的应用中，建议采用15V逻辑电平。
If nuclear selection for CONCEPT drive voltage level is higher than 5 v, it should be as close as possible to drive placed at the input to a voltage divider.
Please refer to the application guide the AN - 1101.