Two buck converters from Diodes reduce component count in consumer products
Two buck converters from Diodes, the AP62500 and AP62800, have continuous output ratings of 5.0 and 8.0A respectively. These are the latest additions to Diodes’ synchronous buck converter portfolio and offer the flexibility engineers need to develop point of load (PoL) solutions that are optimised for either efficiency or size, said the company.
They minimise component count, for compact devices targeted for consumer products, such as 5V and 12V distributed power bus supplies, TVs and monitors, white goods and small home appliances, FPGA, DSP and ASIC supplies, home audio, network systems, gaming consoles, consumer electronics, and general purpose PoLs.
Both buck converters have wide input voltage ranges. The AP62500 covers 4.5 to 18V and the AP62800 covers 4.5 to 17V (making both suitable for 5.0 and 12V rail applications). Their output voltages can be adjusted down to 0.6V. There are three selectable switching frequencies – 400kHz, 800kHz and 1.2MHz. This allows engineers to prioritise elevated conversion efficiency or focus on having a compact form factor. The converters also have three selectable operating modes – pulse frequency modulation (PFM) for improved light-load efficiency, pulse width modulation (PWM) for reduced output voltage ripple, and ultrasonic (USM) for avoiding audible frequency range while ensuring the switching frequency stays above 20kHz.
On resistance (RDSon) figures are kept low in relation to both the high side MOSFET (47mOhm for the AP62500 and 22mOhm for the AP62800) and low side MOSFET values of 18mOhm for AP62500 and 10mOhm for AP62800. This helps to improve step-down conversion efficiency levels, explained Diodes. A low quiescent current (IQ) is also achieved while in PFM mode (195 microA typical), further enhancing light load efficiencies.
The design of these buck converters minimises electromagnetic interference (EMI) issues. A proprietary gate driver design mitigates switching node ringing without having to extend MOSFET turn on / turn off times, which would otherwise impact high frequency switching capabilities. Constant on-time control results in fast transient response and low output voltage ripple. It also facilitates better loop stabilisation. The soft-start time adjustability feature protects against the risk of damage from inrush currents.
Both the AP62500 and the AP62800 are supplied in 12-pin V-QFN2030 packages.
