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The venerable Stephen Woodward recently published the design idea (DI) “Flip ON flop OFF” that converts a momentary push button to a classic push-on, push-off switch. Figure 1 is an attempt to go further still in terms of economy.

The circuit shown in Figure 1 utilizes only one half of a dual D-type package and one more capacitor to the original parts count. It also incorporates an RC power on set (or reset), to guarantee the initial state of the switch when power is applied.

Figure 1 U1A debounces SW1 via R1 & C2 so U1A can reliably toggle.

Wow the engineering world with your unique design: Design Ideas Submission Guide

The initial state of the switch is determined by the Set pin of U1A following the rising voltage on the power input due to the initial discharged state of C1. Capacitor C1 then charges towards ground leaving the flip-flop with the Q output high and the PMOS off.

Alternatively, this RC power on Set circuit can be wired to the Reset pin to change the initial power on state of the switch. The device ESD clamping diodes provide the capacitor discharge path when power is turned off.

The D-type flip-flop is essentially connected in the familiar way of Q-bar to D-input to form a bistable with each clock rising edge toggling the output state. However, in this case the combination of R1 and C2 form a delay network which prevents rapid changes on the D-input, thus effectively de-bouncing the switch by inhibiting state changes until C2 has charged/discharged to the state on the Q-bar output.

—Chris Nother built a discrete Tx/Rx for model aircraft at an early age, later discovering the dreaded “Mains Hum” in a home built “Dinsdale” Hi-Fi amplifier. Employed in R&D using the then newly available available CMOS logic from Motorola and Nat-Semi, career changes to Mainframe Computers, design of disk drive automated test equipment and storage solutions, finally turning full circle in retirement to the hobby that started it all.

Related Content

• Flip ON flop OFF
• Use an op amp as a set/reset flip-flop
• New VFC uses flip-flops as high speed, precision analog switches
• CMOS flip-flop used “off label” implements precision capacitance sensor

The post Latching D-type CMOS power switch: A “Flip ON Flop OFF” alternative appeared first on EDN.

Steel soldering is a metal-joining process used to bond steel components by melting a filler metal with a lower melting point than the steel itself. Unlike welding, which fuses the base metals together, or brazing, which uses higher temperatures, soldering operates at relatively low temperatures (typically below 450°C or 840°F). This makes it suitable for delicate applications where excessive heat could damage the materials.

Soldering steel is more challenging than soldering other metals like copper or brass due to steel’s oxidation properties and lower thermal conductivity. To ensure a strong joint, fluxes and specialized soldering materials, such as tin-lead or silver-based alloys, are commonly used.

How Steel Soldering Works

Steel soldering follows a systematic approach that involves surface preparation, application of heat, and bonding with the help of solder and flux. The key principle behind the process is capillary action, where the molten solder flows into the microscopic gaps between metal surfaces, creating a strong mechanical and electrical bond.

The success of steel soldering depends on various factors, including the type of flux, the choice of solder alloy, and the precision of temperature control. Proper surface cleaning and oxide removal are crucial to achieving a reliable bond, as steel tends to develop an oxide layer that inhibits solder adhesion.

Steel Soldering Process

The steel soldering process consists of several essential steps. First, surface preparation is crucial. The steel surfaces must be cleaned thoroughly using sandpaper, steel wool, or chemical cleaners to remove dirt, grease, and oxidation. Once cleaned, an appropriate flux, such as zinc chloride or rosin-based flux, is applied to prevent oxidation and promote solder flow.

Next, selecting the right solder and flux is important. Lead-free solder alloys such as silver-based or tin-copper alloys are recommended for environmental safety. The flux should be compatible with the solder alloy to ensure proper wetting and adhesion.

The heating process follows, where a soldering iron, torch, or induction heating is used to bring the steel to the required temperature. Uniform heating is necessary to avoid weak joints and improper solder flow. Once the joint reaches the solder’s melting point, the solder wire or paste is introduced. The molten solder then flows into the joint through capillary action.

After soldering, the joint should be allowed to cool naturally without disturbance to prevent cracking. Once cooled, residual flux and oxidation are removed using warm water or specialized cleaning agents to ensure long-term durability.

Steel Soldering Uses & Applications

Steel soldering finds applications in a wide range of industries due to its ability to create strong, reliable joints at low temperatures. In the electronics and electrical industry, it is used in circuit boards, connectors, and electrical components where steel parts need reliable connections. It is also utilized for shielding applications for electromagnetic interference (EMI) protection.

In the automotive and aerospace industries, steel soldering is employed in small, heat-sensitive components, such as sensors and electrical connectors. Aerospace applications require precise soldering of critical parts to maintain structural integrity.

The HVAC systems and plumbing industries also benefit from steel soldering, particularly in joining refrigeration coils, pipe fittings, and heat exchangers. This method provides leak-proof and corrosion-resistant joints essential for efficient system performance.

Additionally, steel soldering is widely used in jewellery making and artistic metalwork. It allows artisans to create custom metal pieces, repair jewellery, and design decorative steel structures while maintaining an aesthetically pleasing finish. The medical industry also utilizes steel soldering in the manufacturing of surgical instruments and medical devices, ensuring precise and biocompatible metal bonding.

Steel Soldering Advantages

Steel soldering offers several advantages over other metal joining methods, making it an ideal choice for specific applications. One major advantage is its low heat requirement. Unlike welding, which involves high temperatures that can cause warping or damage, soldering operates at much lower temperatures, preserving the integrity of delicate components.

Another significant benefit is its versatility. Steel soldering can be used on thin or intricate steel components without compromising their structural integrity. The process creates strong and reliable bonds that are resistant to corrosion, ensuring long-term durability.

Cost-effectiveness is another advantage, as soldering requires minimal equipment and energy compared to welding and brazing. This makes it an economical choice for small-scale manufacturing and repairs. Moreover, soldering is relatively easy to learn and perform, requiring minimal training and no specialized machinery, making it accessible to both professionals and hobbyists.

A notable safety advantage is that soldering does not require specialized protective equipment. Unlike welding, which necessitates protective gear against UV radiation and fumes, soldering is a safer process with fewer health hazards.

Steel Soldering Disadvantages

Despite its benefits, steel soldering has certain limitations. One major drawback is that soldered joints are not as strong as welded joints, making them unsuitable for high-load applications. Additionally, soldered joints have limited heat resistance and may fail under high temperatures, restricting their use in environments where elevated temperatures are a concern.

Another challenge is oxidation. Steel tends to form an oxide layer quickly, which can hinder solder adhesion. This requires the use of aggressive fluxes or pre-cleaning treatments to ensure a strong bond. Environmental concerns also arise with traditional lead-based solder, as it poses health and environmental risks, leading to a shift toward lead-free alternatives.

Lastly, some fluxes used in the soldering process leave corrosive residues that must be thoroughly cleaned to prevent long-term damage to the joint. Proper cleaning procedures are necessary to maintain joint integrity and prevent issues such as corrosion or weak bonding over time.

Conclusion

Steel soldering is a valuable technique for low-temperature metal bonding, offering numerous advantages in electronics, automotive, HVAC, and medical applications. While it has certain limitations, proper material selection, surface preparation, and soldering techniques can help achieve strong and reliable bonds. As advancements in soldering technology continue, steel soldering is becoming even more efficient and environmentally friendly, making it a crucial method in modern manufacturing and repair industries.

The post Steel Soldering: Definition, Process, Working, Uses & Advantages appeared first on ELE Times.

On 25 March, Tokyo-based Mitsubishi Electric Corp will begin shipping samples of a new 16W-average-power gallium nitride (GaN) power amplifier module (PAM) for 5G massive MIMO (mMIMO) base stations. Operating in the 3.6–4.0GHz band, it can be widely deployed in North America and East and Southeast Asia. As 5G networks expand from urban centers to regional areas, mMIMO base stations, especially 32T32R mMIMO base stations (consisting of 32 transmitters and receivers), are expected to be increasingly deployed. Mitsubishi Electric says that its 16W GaN PAM is particularly suited to 32T32R mMIMO base stations because it reduces both production costs and power consumption...

Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA — which makes enhancement-mode gallium nitride on silicon (eGaN) power field-effect transistors (FETs) and integrated circuits for power management applications — has introduced the EPC2367, a next-generation 100V eGaN FET that delivers high performance and efficiency as well as lower system costs for power conversion applications...

Intelligent power and sensing technology firm onsemi of Scottsdale, AZ, USA has introduced the first generation of its 1200V silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET)-based SPM 31 intelligent power modules (IPMs). EliteSiC SPM 31 IPMs deliver the highest energy efficiency and power density in the smallest form factor compared with using Field Stop 7 IGBT technology, it is claimed, resulting in lower total system cost than any other leading solution on the market...

💼 Оголошується конкурс на заміщення посад наукових працівників kpi вт, 03/18/2025 - 11:00

Replaced for now. Phasing out this order equipment . submitted by /u/Switchlord518 [link] [comments]

Introduction

The demand for smaller, lighter, and more efficient AC/DC USB power delivery (PD) chargers is always a challenge for power-supply design engineers. Below 100 W, the quasi-resonant flyback is still the dominating topology, and gallium nitride (GaN) technology can push the power density and efficiency further.

However, providing bias power for the primary controller requires an auxiliary winding on the transformer as well as rectifying and filtering circuitry. To make things worse, the USB PD charger output voltage has a wide range. For example, the USB PD standard power range covers output voltages from 5 V to 20 V, and the latest USB PD extended power range allows the output voltage to go as high as 48 V. Since the auxiliary voltage is proportional to the output voltage, the bias voltage range on the primary controller will increase, requiring extra circuitry and degrading efficiency. In this power tip, I’ll introduce a self-biased flyback converter solution to address these design challenges.

Dealing with wide bias voltages

Figure 1, Figure 2, Figure 3, and Figure 4 show four different ways to deal with the wide bias voltage range in USB PD charger applications. Conventional methods include using a linear regulator, a tapped auxiliary winding, or even adding an extra DC/DC switching converter to regulate the bias voltage. All of these methods will increase component count, add cost, or increase power losses. Alternatively, self-biasing totally removes external components and increases efficiency.

Figure 1 Bias circuits for applications with wide output voltage ranges using a discrete linear regulator. Source: Texas Instruments

Figure 2 Bias circuits for applications with wide output voltage ranges using a tapped auxiliary winding. Source: Texas Instruments

Figure 3 Bias circuits for applications with wide output voltage ranges using boost converter. Source: Texas Instruments

Figure 4 Bias circuits for applications with wide output voltage ranges using a self-biased VCC. Source: Texas Instruments

VCC self-biasing

The flyback controller can always get bias power directly from the rectified AC input voltage, but this results in excessive power losses. The key to self-biasing is to harvest energy from the power stage, which can come from two sources. One is the switch-node capacitor stored energy; the other is energy stored in the primary-side winding of the transformer. As shown in Figure 5, an integrated self-biasing circuit can ideally do both, based on the input and output conditions.

Figure 5 The self-bias circuit harvests energy from the switch-node capacitance or magnetizing inductance. Source: Texas Instruments

Figure 6 shows the energy harvesting from the switch-node capacitor. This can save efficiency as it recycles the energy storage in switching node capacitor in every switching cycle. In cases such as AC low-line input when the reflected output voltage is identical to the input voltage, natural zero voltage switching will occur, and there is no energy in the switch-node capacitor, inductor energy harvesting will take effect, where a small portion of the primary switching current is directed to the VCC cap through an internal path.

Figure 6 VCC self-bias operation: (a) capacitor energy harvesting on the switching node and (b) inductor energy harvesting through the primary current. Source: Texas Instruments

Achieving auxless sensing

Many flyback controllers use the auxiliary winding to sense the input and output voltages and detect conditions such as output overvoltage or input undervoltage. With self-biased flyback converters, it is possible to use the switching-node voltage for input and output voltage sensing. As shown in Figure 7, the sensed voltage is the sum of the input and reflected output voltage. Since the average voltage across the primary winding is zero, the average of the switch-node voltage is equal to the input voltage.

For output voltage sensing, it can sample the reflected output voltage, and the controller needs to be informed of the exact turns ratio of the transformer with the use of a resistor-programmable pin [the TR pin in the Texas Instruments (TI) UCG28826].

Figure 7 Auxless voltage sensing where the sensed voltage is the sum of the input and reflected output voltage. Source: Texas Instruments

Once properly configured, self-biased devices such as the UCG28826 can accurately provide various protections like overpower and overvoltage protection. Figure 8 shows the UCG28826 in a USB PD application.

Figure 8 A self-biased USB PD design using the UCG28826 that can accurately provide various protections like overpower and overvoltage protection. Source: Texas Instruments

Figure 9 shows the overvoltage protection waveforms after intentionally disconnecting the feedback pin which is a single fault condition. The controller senses the output voltage and triggers overvoltage protection accordingly when the output ramps up to around 24.4 V for a nominal 20 V output.

Figure 9 Auxless sensing example for overvoltage protection. Channel 1 (CH1) is Vout and channel 2 (CH2) is Vsw. Source: Texas Instruments

Prototype and test result

Figure 10 shows the TI universal AC-input 65W dual USB type-C port USB PD charger reference design with an integrated GaN power switch. Due to the simplified self-bias feature and integrated GaN switch in the UCG28826, the reference design achieves a power density of 2.3 W/cm3 and 93.2% efficiency for the AC/DC stage. The auxless design also simplifies transformer manufacturing and reduces costs. Table 1 summarizes the design parameters of 65 W design for reference. 

Figure 10 A universal AC-input 65-W reference design board. Source: Texas Instruments

Parameter	Value
AC input voltage	90-264 VAC
Output voltage and current	5-20 V, 3.25 A maximum
Transformer	ATQ23-14
Turns ratio	7-to-1
Transformer inductance	200 µH
Switching frequency (full load)	90-140 kHz
Efficiency	93.2% at 90 VAC (AC/DC stage only)
Power density	2.3 W/cm3

Table 1 Universal AC-input 65W reference design parameters.

Simplified USB PD charger

A high-level integration with a controller and GaN switch can simplify USB PD charger design, but the bias circuitry for the controller and associated auxiliary winding on the transformer are still there, degrading efficiency and affecting size and cost. An integrated self-biasing circuit can eliminate that portion of the circuit and increase the power density for power supplies with wide-range outputs. Additionally, it is still possible to achieve proper input and output voltage sensing in the absence of an auxiliary winding on the transformer.

Max Wang is a systems engineer and Member, Group Technical Staff at Texas Instruments. He has over 18 years of experience in the power semiconductor and power-supply industries in computing, industrial, and personal electronics markets; specializing in isolated AC/DC and DC/DC applications. His design and research interests include high-efficiency and high-power-density power conversion, soft-switching converters, and GaN implementation in AC/DC converters. Max obtained a master’s degree in electrical engineering from Zhejiang University in 2006. He has worked at Delta, Power Integrations, Infineon and Texas Instruments.

Related Content

• Ungluing a GaN charger
• USB Type-C PD 3.0 Specification, Charging and Design
• Power Tips #138: 3 ways to close the control loop for totem-pole bridgeless PFC
• Power Tips #127: Using advanced control methods to increase the power density of GaN-based PFC
• Power Tips #115: How GaN switch integration enables low THD and high efficiency in PFC
• Power Tips #131: Planar transformer size and efficiency optimization algorithm for a 1 kW high-density LLC power module

The post Power Tips #139: How to simplify AC/DC flyback design with a self-biased converter appeared first on EDN.

Фемінітиви: що воно таке, звідки взялося й навіщо потрібне kpi пн, 03/17/2025 - 15:26

Візит міністра Кабінету Міністрів України та голова Держспецзв'язку до ІСЗЗІ kpi пн, 03/17/2025 - 15:05