Y. Unno, 2009/2/24 1

Status of Piezo-Transformer DC-DC Converters

Y. Unno (KEK)

M. Imori, Y. Kanada (U. Tokyo)

S. Imada (NF KK)

M. Katsuno (NEC-Tokin KK)

Y. Unno, 2009/2/24 2

Power Supplies with PET• Piezo-Electric Transformer (PET)

InputOutput

PE ceramicsInner elecrode

€

1

2CinVin

2 =1

2CoutVout

2

γ =VoutVin

=CinCout

(Perfect) Transformer ratio is

Advantages of PET:Non-magneticRadiation tolerantIsolation of primary and secondary

Y. Unno, 2009/2/24 3

Development of HV Power Supply

• Status– HV (Step-up PE

T)• 1 kV - 5-10 mA• Evaluating with e

xisting Step-up PET and power supply board

Y. Unno, 2009/2/24 4

Step-up HV PET Evaluation

• Demonstrated! – 1 kV - 5 mA – with existing PET

• Issues– Loss– Ripple

• New optimized PET to come

Source 15 V Load 200 kÉ∂

Output[V]

Freq[kHz]

Output{A]

Ripple[Vp-p] Eff [%]

0 79 0.00 0

500 70.6 2.50 5.4 12%

602 69.5 3.01 6.6 17%

704 68.3 3.52 8 27%

802 67.5 4.01 9.6 34%

903.4 67 4.52 11 39%

1000 66.5 5.00 12 47%

1102 65.8 5.51 14 50%

1202 65.4 6.01 16 53%

Y. Unno, 2009/2/24 5

Development of LV Power Supply

• LV (Step-down PET)– Goal: 2V - 4 A– New fabrication of co

mpact Step-down PET

• 14 mm x 14 mm x 4 mm

– Power supply test board has been fabricated

Y. Unno, 2009/2/24 6

Step-down LV PET

• Demonstrated!– 2V - 4A– Drive voltage: 48 V

• PET Efficiency ~80%– excluding drive circuit

power

SourceCurrent[mA]

DriveCurrent[mA]

OutputVoltage[V]

OutputCurrent[mA] Efficiency

50 0.0 0.0%22 0.0 0.0%10 0 0.0%

5 35 104 1.995 399 27.3%2 35 148 1.995 997.5 50.1%1 35 240 1.995 1995 64.4%

0.5 35 480 1.994 3988 66.6%

Y. Unno, 2009/2/24 7

Summary• Step-up HV PET power supply

– 1 kV - 5 mA achieved– Issues identified

• A compact Step-down LV PET is fabricated– 2 V - 4 A achieved– PET efficiency ~80%

Y. Unno, 2009/2/24 8

Backup

Y. Unno, 2009/2/24 9

High Voltage Power Supply Incorporating Piezoelectric

Transformer

Masatosi Imori, Yoshinobu Unno1, Yasumasa Kanada2, Satoru Imada3 and Masafumi Katsuno4

ICEPP, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033,Japan1KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 Japan2Information Technology Center, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku Tokyo 113-8658, Japan3NF Corporation, 6-3-20 Tsunashima Higashi, Kohoku-ku, Yokohama-shi 223-8508, Japan4NEC TOKIN Corporation, 7-1, Kohriyama 6-chome, Taihaku-ku, Sendai-shi, 982-8510, Japan

Y. Unno, 2009/2/24 10

Commercial Product - Example• 60 independent channels of HV power supply are housed in 2U

x 19’’ EURO crate x 50 cm in depth– Each board contains 3 ch. of HV power supply– The system consists of 20 HV boards & a control board

• A piezoelectric transformer (PT) generates high voltage

Y. Unno, 2009/2/24 11

Commercial Product (cont'd)• output capability

– 4 kV 100 A with ripples less than 100 mV in peak-to-peak voltage– Capable of driving 10 M up to 4 kV

• magnetic field tolerance– Working under the magnetic field of 1 Tesla

• Radiation Hardness– 60 MeV protons ; 1E11 (~14krad) [tested at PIF @ PSI ]– Cobalt-60 gamma-ray ; ~300kradthe system cope with both conditions

Y. Unno, 2009/2/24 12

Issues to Apply SCT

• Output capacity– 1 kV-5 mA, -10 mA?

• Ground isolation• Regulation of output voltage• Radiation tolerance

– if HV units are to be placed near the inner detector, e.g., outside the calorimeter

Y. Unno, 2009/2/24 13

Piezoelectric HV Transformer

• Max. efficiency x Cd2 x Ｚ out to be1 =1/sqrt(L1*(C1+Cd1)), ...

• Mostly a few W range– E.g., 5W = 1 kV * 5 mA

Y. Unno, 2009/2/24 14

Sharing Common Ground The PT used in the power s

upply shares the common ground between the primary and the secondary

Potential Difference

Current

Y. Unno, 2009/2/24 15

Ground Isolation

• How to power the monitoring circuitries– With/Without floating voltage sources– Isolation couplers

Large Impedance