Archive : 6 February 2008 год

Wolfson Microelectronics announces an addition to its AudioPlus Smart Power product line. The WM8400 combines a multimedia CODEC with integrated power management features. WM8400 functions include a multimedia CODEC, on-chip FLL, two DC-DC converters and four LDO regulators, all inside a compact 6x6mm BGA package. Flexible hardware control enables the WM8400 to support the generic power management needs of multimedia companion processors. The device incorporates a low power audio CODEC, which delivers 98dB SNR performance and supports the signal switching, audio conversion and voice mixing requirements of next-generation mobile phones.

The digital core can be as low as 5mW during a voice call. In addition, the WM8400’s CODEC is able to select, in software, Class AB or Class D speaker driver operation meaning handset designers can deploy filterless Class D technology into a wider range of increasingly diverse, handheld form factors, where restrictions such as noise and interference previously demanded a Class AB driver topology. System designers may select the most appropriate mode of operation for the anticipated usage scenario, allowing battery life for the end user to be maximised. The WM8400 also includes a 1W mono speaker driver. Four headphone driver outputs support conventional, fully differential or cap-less drive. Multiple microphone or analogue line inputs (mono or stereo, single-ended or differential) can be supported and a programmable high-pass filter is provided to remove low frequency noise from the input signal.

The digital audio interface supports most commonly-used data formats and clocking schemes while time-division multiplexing and an additional DAC interface provide additional flexibility. From a power management perspective, the WM8400 includes two programmable 2MHz DC-DC step-down (Buck) converters, four low-dropout (LDO) regulators. The startup sequence and default voltages for the core regulators; DC-DC1, DC-DC2, LDO1 and LDO2 are selectable in hardware via external pins, and all regulators are also software programmable. The core regulators are intended to power the multimedia application processor sub-system while LDO3 and 4 are specifically designed to power the on-chip audio CODEC.

The WM8400 is available for sampling now in a 105-pin 6x6mm BGA package.

Toshiba Electronics Europe has announced a multi-motor driver IC with valuable integrated features, allowing engineers to establish a common hardware solution to driving multiple stepper motors or brush DC motors. The TB62237BFG uses Toshiba’s high-voltage IC technology to combine four H-bridge outputs with motor-control logic for stepper and brush DC motors, as well as three DC-DC converters, a built-in timer and protection functions. This creates a highly integrated solution for single-, dual- and quadruple-axis motor driving duties. The DMOS motor-driver outputs achieve on-resistance of 0.6Ω for low-loss operation.

With two 16-bit shift registers, each equipped with a latch, the IC is capable of driving any combination of stepper and brushed DC motors up to a maximum of four axes. Each of the four H-Bridges can be programmed to accommodate either a stepper configuration with 4-bit micro stepping or a DC brushed one. Since parallel operation of each two H-Bridges is also supported the designer has the choice to drive fewer motor axes but with higher current. High-speed chopping at up to 150kHz is possible, controlled by an external oscillator. Motors operating at an input voltage up to 40V can be driven, and the maximum standard motor-driving current is 6.4A per bridge. This can be increased to 8.0A for single- or dual-axis operation by connecting the device’s H-bridge pairs using external jumpers. Four selectable mixed decay schemes optimise performance for stepper motor drives.

There are three independent DC/DC converters each one allowing for output currents up to 1.2A and by parallel operation of two converters a maximum of 2.4A can be realised. Additional on-chip features include a built-in timer that starts running when the IC is supplied with power, which can be used to initialise external devices. A Reset block is also implemented on-chip, making it possible to deliver an external reset signal. In addition, the TB62237BFG implements protection functions to prevent damage to the motor as well as the IC without requiring external components. Protection functions include over-current and over-voltage protection for internal DC-DC converters, as well as motor over-current protection and IC over-temperature protection.

The device is delivered in a 64-pin QFP surface-mount package featuring a metal plate on the bottom side which can be soldered directly to a suitable copper plane on the printed circuit board resulting in efficient cooling.