By, Andrew Berry, Principal Product Modelling Engineer, Nexperia Many manufacturer-provided simulation models are available for use when designing with discrete power MOSFETs. However, few (if any) accurately represent real-world performance, reducing their use when using tools such as SPICE to simulate practical applications. Temperature is always a factor in power design, and many models are […]
FAQ
What are triacs, diacs and quadracs good for?
Triacs, diacs, and quadracs are ac power control semiconductor devices used in line frequency applications such as lighting control, motor speed control, and temperature modulation. They can be found in consumer and industrial settings. Triacs are a member of the thyristor family and have a four-layer structure. Diacs (DIode AC switch) are used to trigger […]
What’s the difference between Shockley and Schottky diodes?
Neither a Shockley diode nor a Schottky diode are single p-n junction devices. A Shockley diode has a four-layer thyristor structure with a typical forward drop of 800 mV. It’s called a diode because it has two leads. A Shockley diode is essentially a SCR with the gate not connected. In a Schottky diode a […]
Design tips for high-voltage protection in EVs and hybrids
The primary goal of EV protective circuits: Keep vehicle occupants safe day-to-day and first-responders protected if the worst happens. Michael Zimmermann, Littelfuse, Inc. The 12-V automotive battery may become a relic of the past as electric vehicles (EV) and hybrid cars gain market share. EVs and hybrid vehicles use battery packs of at least 500-V […]
How do phase control, bidirectional, and bypass thyristors work?
Thyristors are four-layer semiconductor switches with alternating layers of P- and N-type materials. While all thyristors share the same basic structure, the details of their implementation and packaging can be modified to meet the needs of specific applications. This FAQ reviews basic phase control thyristor (PCT) operation, then looks at the use of bidirectional controlled […]
What’s the difference between an IGBT and an IGCT?
IGBTs and IGCTs are four-layer devices that don’t look that different at first glance. But, when you ‘look under the hood’, you find that an insulated gate bipolar transistor (IGBT) and an integrated (sometimes called ‘insulated’) gate commutated thyristor (IGCT) aren’t that similar. A bipolar transistor forms the basis of an IGBT, while an IGCT […]
Bidirectional power supplies support new UPS requirements, Part 2
Bidirectional power supplies dynamically direct power from multiple sources to different loads, some of which are also power sources at other times. In recent years, there’s has been a dramatic increase in the need for bidirectional AC/DC and DC/DC power supplies, in addition to the unidirectional supply of a traditional UPS. That supply takes a […]
How does a silicon controlled rectifier work?
A silicon controlled rectifier (SCR) is a four-layer power semiconductor device. The term ‘silicon controlled rectifier’ was coined by General Electric when SCRs were first introduced in 1957. Like rectifiers, SCRs are unidirectional devices. Today, SCRs are recognized as a type of thyristor. Other types of thyristors, such as triacs, are inherently bidirectional. This FAQ […]
Bidirectional power supplies support new UPS requirements: Part 1
Bidirectional power supplies dynamically direct power from multiple sources to different loads, some of which are also power sources at other times. We recently had a short-term power failure in the neighborhood due to a storm and a downed tree. As the outage lasted only about eight hours, it was a minor inconvenience in the […]
The humble neon lamp: down, but definitely not out, Part 3
Despite the convenience and availability of LEDs, the neon lamp still has a viable position as a power-on indicator as well as use in some specialty applications. Thus far, we have looked basic neon lamp principles and operation. This part looks at some special issues related to these versatile indicators. Q: Why use a neon […]