Maxim simplifies in-car recharging of USB-enabled devices
Maxim Integrated has come up with a single chip solution to overcoming an ongoing problem facing mobile device users using long USB cables that do not fully recharge. It is their just introduced MAX16984 automotive DC-DC converter with USB charge emulator.
Previously, said Ben Landen, Automotive Business Manager at Maxim Integrated, PDs like smartphones and tablets could not charge reliably from OEM stock USB ports in vehicles.
“Long embedded USB cables cause a voltage drop and reduce charging current, resulting in a PD to not properly charge,” he said. “Also, low-cost portable USB car chargers introduce RF interference.”
While automotive system designers could find workarounds to this problem, it usually required at least three chips.To reduce that functionality to a single chip, said Landen, Maxim engineers combined a low EMI 5V automotive-grade DC-DC converter capable of driving up to 2.5A with dynamic voltage adjustment, which is essential for charging contemporary PDs over long automotive embedded cables.
In addition, said Landen, it also incorporates a USB Battery Charging Specification v1.2-compliant charge emulator, which conducts the necessary handshake between the PD and upstream host instructing the PD to increase its charge current.
Finally, to deal with the RF problems, they have in the MAX16984 incorporated ESD diodes and USB over voltage protection switches, which provide robust industry-leading fault protection.
The result is what he claims is the fastest and most reliable PD charging with the smallest solution size, ideal for automotive radios and navigation modules, embedded telematics and connectivity modules, and USB-dedicated charging ports.
The 5V automotive-grade DC-DC converter is capable of driving up to 2.5A and operates from a voltage up to 28V and is protected from load dump transients up to 42V. An integrated output adjustment, he said, eliminates cable voltage drop.
The MAX16984’s automotive USB function communicates with a connected PD and switches to low-power mode when not in use, thus further reducing power consumption.