Is GaN Leading the Battery Charging Revolution

Charging systems for Electric Vehicles (EVs) and Hybrid Electric Vehicles (HEVs) are critical to powering the batteries and ultimately allowing them to operate efficiently. They fall into two broad categories: off-board charging systems and on-board charging systems.

Types of batteries that cannot be recharged:
Non-rechargeable batteries, also known as primary batteries, are designed to be used once and then discarded:
- Classic lead-acid batteries power electric motors, scooters, or bicycles, for example.
- Alkaline batteries (Kirkland has AA and AAA versions)
- 9V Duracell Batteries
- C batteries
- Lithium batteries are non-rechargeable (primary) and use lithium metal in the electrodes.
Rechargeable battery type:
These batteries can be recharged and used multiple times, making them a more cost-effective and environmentally friendly option in the long run. Devices that typically contain rechargeable batteries include:

- Lithium-ion batteries are secondary batteries that are used in iPhones, computers, and electric cars. These batteries use a non-metallic compound of lithium ions. They are lighter, have a higher energy density, and have a higher charge density than lithium batteries.
- Lead-acid batteries
- Nickel-cadmium (NiCd) batteries
- Nickel Metal Hydride (NiMH) Batteries

Understanding Battery Ratings
Lead-acid batteries list a voltage rating, such as 12 V (make sure your battery charger is rated for 12V), and an Ampere-hour (Ah) rating, such as 7 Ah/20 HR, which indicates the capacity of the battery. Now, divide 20 by 7 and we have the number of amps that can be discharged in 20 hours.

Or use a 36 V lithium-ion battery (again, make sure the battery charger is rated for 36 V) and 30,000 mAh. it's a little larger than a lead-acid battery. This is a battery pack containing multiple individual cells connected in parallel and series to achieve voltage and amp-hour ratings. In addition to the wired charging terminals, the circuitry inside the battery pack includes terminal wires (most with connectors).

There are several types of chargers. Smart chargers have the electronics to safely charge the battery and have the ability to stop charging when the battery reaches a certain level. Typically, battery chargers have a red charge indicator and a green indicator when fully charged. Most chargers plug into a standard electrical outlet between 100 and 240 V @ 50/60 Hz. Charger output is measured in amps.

Shallow discharging and recharging are much better than full charging because they put less stress on the battery, so it will last longer. When discharging a battery, Battery University recommends that you only allow it to reach 50% before recharging it. When recharging, avoid pushing a lithium-ion battery all the way to 100%.

Benefits of Gallium Nitride Chargers
Gallium Nitride (GaN) battery chargers are typically smaller than most chargers in the industry. This is because they can conduct higher voltages over time than their silicon counterparts. Capacities are typically 20 to 300 W.

GaN chargers are also more efficient at transferring current, which means less energy is lost to heat. As a result, more energy will flow to the device being charged.

GaN chargers also have higher switching frequencies for faster wireless power transfer. GaN semiconductors typically cost more than silicon. However, because of the increased efficiency, there is less reliance on additional materials such as heat sinks, filters and other circuit components. This also has the potential for cost savings of 10% to 20%. This figure shows an example of a GaN-based car charger from Texas Instruments (TI).

Next-Generation Charging Standards: USB-C PD 3.0 and PPS
The latest GaN chargers utilize USB-C powered (PD) charging technology. They support up to 300 W of power and enable the device and charger to communicate with each other to determine the optimal charging power. So when a laptop requiring 65W of power is plugged in, the charger will be able to recognize it and automatically adjust to the power of the other port.

USB-C PD is compact enough to be used for small, thin and light devices such as smartphones. However, it can also charge larger devices such as laptops.

The Programmable Power Supply (PPS) standard is an advanced charging technology for USB-C devices. It allows the voltage and current to be modified in real time based on the device's state of charge to provide maximum power.

In this regard, the USB Implementers Forum (USB-IF) is a non-profit organization that supports the marketing and promotion of the Universal Serial Bus (USB). The organization added PPS fast charging to the USB PD 3.0 standard in 2017. Data can now be exchanged every 10 seconds with the ability to dynamically adjust the output voltage and current based on the specifications of the receiving device.

The main advantage of PPS over other standards is its ability to reduce conversion losses during charging. As a result, less heat is generated, which helps extend the life of the device's battery.

Why charge with GaN?
GaN technology has significantly accelerated the charging of hybrid and hybrid-electric vehicles. GaN on-board chargers in EVs have capacities from 20 to 300 W, ranging from one USB-C port to two or as many as three. Some even include USB-A charging ports to accommodate EVs with older cable technologies. Several of the latest GaN chargers support USB-C PD and PPS, bringing greater versatility to EV charging designs.

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