January 2011

Doc ID 18163 Rev 1

1/13

AN3302

Application note

Monolithic power management for high definition ODD with

true shutdown, reset, and programmable step-up voltage

Introduction

Blu-ray disc players have grown rapidly in popularity due to the increasing availability of

digital services and high definition digital media content.

This application note describes how to use STODDO1, a complete power management for

BIu-ray disc players, based on high density optical storage devices. It integrates two step-

down converters and one step-up.

The step-down converters are optimized for powering Iow-voltage digital core, up to 0.8 A, in

ODD applications and, generally, to replace a high current linear solution when the power

dissipation may cause an overheating of the application environment.

The step-up provides the needed voltage for supplying the blue laser in mobile applications

where only 5 V is available. The output voltage is programmable, by using S-wire protocol, in

the range of 6.5 V to 14 V, with a current capability of 0.7 A.

Figure 1.

Blu-ray disc player power management architecture based on STODD01

obtaining high efficiency.

The enable function for the step-up section, and reset function for monitoring the input

voltage, make the device particularly suitable for optical storage applications.

The high switching frequency (1.2 MHz typ.) allows the use of tiny surface-mounted

components. Furthermore, a low output ripple is guaranteed by the current mode PWM

topology and by the use of X7R or X5R and low ESR SMD ceramic capacitors.

The device includes soft-start control, thermal shutdown, and peak current limit, to prevent

damage due to accidental overload.

6 to 12 V

Motor

Control IC

Flash

DRAM

DSP

5 V

5 V

Step Down

ADJ 700 mA

Step Down

3.3 V 700 mA

1.2 V

3.3 V

Motors

5 V

Reset IC

Reset

BLUE Laser Driver

Step Up

ADJ 800mA

STODD01

AM07854v1

6 to 12 V

Motor

Control IC

Flash

DRAM

DSP

5 V

5 V

Step Down

ADJ 700 mA

Step Down

3.3 V 700 mA

1.2 V

3.3 V

Motors

5 V

Reset IC

Reset

BLUE Laser Driver

Step Up

ADJ 800mA

STODD01

AM07854v1

www.st.com