Ischia, giugno 2006Riunione Annuale GE 2006 An innovative PWM loop control for VRMs An innovative PWM loop control for VRMs D.I.E.E.T. – Università di Palermo Ing. Giuseppe Maria DI BLASI Ing. Valeria BOSCAINO Ing. Patrizia LIVRERI Prof. Ing. Giuseppe CAPPONI I&PC Division – STMicroelectronics Ing. Filippo MARINO Ing. Marco MINIERI Power Applications Lab DIEET i&p industrial & power conversion division

Ischia, giugno 2006Riunione Annuale GE 2006 Outline Introduction Introduction Innovative current-sensing Innovative current-sensing Two-module interleaved buck converter Two-module interleaved buck converter Prototype experimental results Prototype experimental results Conclusion Conclusion

Ischia, giugno 2006Riunione Annuale GE 2006 Future generations of microprocessors: Supply Voltage < 1V Supply Current > 100A Faster transient slew rate (100A/s) Introduction (1) Increasing speed data processing Decreasing power consumption

Ischia, giugno 2006Riunione Annuale GE 2006 Introduction (2) Large amount of output filter and on-board decoupling capacitors Low efficiency Large ripple of steady-state output signal

Ischia, giugno 2006Riunione Annuale GE 2006 Introduction (3) Multi-module interleaved buck converter Low occupied space Low cost Current-sharing control current sensing The most important function on VRM applications is current sensing Good steady-state and transient performances

Ischia, giugno 2006Riunione Annuale GE 2006 R2R2 C2C2 Current-voltage (IV) control loop Innovative current-sensing (1) Innovative sense to generate saw-tooth Patent pending Innovative IV loop

Ischia, giugno 2006Riunione Annuale GE 2006 Current-voltage (IV) control loop Innovative current-sensing (2) Current-mode topology Simple current-sensing and current-sharing implementation No dissipative elements introduced No limitations of traditional current-mode control

Ischia, giugno 2006Riunione Annuale GE 2006 Two-module interleaved buck converter Input voltage: V dc = 12V Output voltage: V o = 1V Switching frequency: f s = 250kHz Output current: I o = 1÷60A Output current slew-rate: S.R. = 60 A/μs Maximum dynamic output voltage ripple: V o 30mV

Ischia, giugno 2006Riunione Annuale GE 2006 Prototype experimental results (1) Sensing signal at 1A load Saw-tooth 0 3.6V Saw-tooth signal has the same waveform of inductor current

Ischia, giugno 2006Riunione Annuale GE 2006 Prototype experimental results (2) Sensing signal at 20A load Saw-tooth 0 4V Saw-tooth signal has the same waveform of inductor current

Ischia, giugno 2006Riunione Annuale GE 2006 Prototype experimental results (3) I OUT =30A Adaptive Voltage Positioning

Ischia, giugno 2006Riunione Annuale GE 2006 Prototype experimental results (4) I OUT =30A

Ischia, giugno 2006Riunione Annuale GE 2006 Conclusion New current-sensing technique is proposed New current-mode control is implemented Experimental results on two-module buck converter are excellent