AN2503

PDP Sustain circuit

11/30

Figure 12.

Circuit scheme

Weber topology provides a new sustainer circuit that recovers the energy otherwise lost in

charging and discharging the panel capacitance, Cp. The efficiency with which the sustainer

recovers this energy is defined as the "recovery" efficiency. In particular, when Cp is

The recovery efficiency is defined by:

Equation 1

energy recovery.

It is worth noting that the recovery efficiency is not the same as the conventional power

efficiency defined in terms of the power delivered to a load, since no power is delivered to

the capacitor Cp. It is simply charged and then discharged. The recovery efficiency is a

measure of the energy loss in the sustainer, and could reach a value higher than 90%.

Summarizing, the panel's pixels are connected in parallel and can be represented as an

equivalent panel capacitor Cp. A proper switching sequence, together with the energy

recovery circuit, allows this circuit to produce an AC voltage required to illuminate, recover

residual energy and reset the cells of the panel.

Referring to the schematic in Figure 12, Power devices in the Sustain circuit topology can be

grouped into four circuit sub-functions:

1.

Energy recovery circuit (ERC) which consists of T1, T2, T11, T12, D1, D2, D3, D4, D5,

D6, D7, D8

2.

Sustain circuit (discharge circuit or sustainer) which consists of T3, T4, T9, T10

3.

Path circuit which consists of T5, T6

4.

Set and Reset circuit which consists of T7, T8

Vs

Vs

Vs

Vset

L7

T9

T10

T8

T12

T11

-Vreset

Cp

CS1

CS2

L1

D7

D8

D6

D5

T7

D1

Vs

T3

T2

T1

T4

T6

T5

D2

D4

D3

Eff

100

C

2

E

LOST

–

C

2

-----------------------------------------

100

1

E

LOST

C

2

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–

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⎜⎟

⎛⎞

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