CAPZero™ Family

Zero1 Loss Automatic X Capacitor Discharge IC

Product Highlights

• Blocks current through X capacitor discharge resistors when

AC voltage is connected

• Automatically discharges X capacitors through discharge

resistors when AC is disconnected

• Simplifies EMI filter design – larger X capacitor allows smaller

inductive components with no change in consumption

• Only two terminals – meets safety standards for use before or

after system input fuse

• >4 mm creepage on package and PCB

• Self supplied – no external bias required

• High common mode surge immunity – no external ground

connection

• High differential surge withstand – 1000 V internal MOSFETs

EcoSmart® – Energy Efficient

• <5 mW consumption at 230 VAC for all X capacitor values

Applications

• All ACDC converters with X capacitors >100 nF

• Appliances requiring EuP Lot 6 compliance

• Adapters requiring ultra low no-load consumption

• All converters requiring very low standby power

Description

When AC voltage is applied, CAPZero blocks current flow in the

X capacitor safety discharge resistors, reducing the power loss to

less than 5 mW, or essentially zero1 at 230 VAC. When AC

voltage is disconnected, CAPZero automatically discharges the

X capacitor by connecting the series discharge resistors. This

operation allows total flexibility in the choice of the X capacitor to

optimize differential mode EMI filtering and reduce inductor costs,

with no change in power consumption.

Designing with CAPZero is simply a matter of selecting the

appropriate CAPZero device and external resistor values in Table 1

for the X capacitor value being used. This design choice will

provide a worst case RC time constant, when the AC supply is

disconnected, of less than 1 second as required by international

safety standards.

The simplicity and ruggedness of the two terminal CAPZero IC

makes it an ideal choice in systems designed to meet EuP Lot 6

requirements.

The CAPZero family has two voltage grades: 825 V and 1000 V.

The voltage rating required depends on surge requirement and

circuit configuration of the application. See Key Applications

Considerations section for details.

R1

D1

MOV

AC

X Capacitor

and Other

EMI Filter

Components

D2

CAPZero

R2

PI-6599-110711

Figure 1. Typical Application – Not a Simplified Circuit.

Component Selection Table

Product3

BVDSS

Maximum Total

X Capacitance

CAP002DG

CAP012DG

CAP003DG

CAP013DG

CAP004DG

CAP014DG

CAP005DG

CAP015DG

CAP006DG

CAP016DG

CAP007DG

CAP017DG

CAP008DG

CAP018DG

CAP009DG

CAP019DG

825 V

1000 V

825 V

1000 V

825 V

1000 V

825 V

1000 V

825 V

1000 V

825 V

1000 V

825 V

1000 V

825 V

1000 V

≤ 500 nF

750 nF

1 mF

1.5 mF

2 mF

2.5 mF

3.5 mF

5 mF

Total Series

Resistance2

(R1 + R2)

1.5 MW

1.02 MW

780 kW

480 kW

360 kW

300 kW

200 kW

150 kW

Table 1. Component Selection Table.

Notes:

1. IEC 62301 clause 4.5 rounds standby power use below 5 mW to zero.

2. Values are nominal. RC time constant is <1 second with ±20% X capacitor and

±5% resistance from these nominal values.

3. Packages: D: SO-8.

www.powerint.com

November 2011

--------------------------------------------
CAPZero Family

R1

AC CEXT

D1

MOVPOS1

CAPZero

D2

R2

X Capacitor1

MOVPOS2

Other EMI

Filter

Components

X Capacitor2

PI-6600-110711

Figure 3. Placement Options of MOV and CEXT.

Key Application Considerations

Breakdown Voltage Selection

Figure 3 illustrates possible system configurations influencing

the choice of CAPZero breakdown voltage. The system

configuration variables include the placement of the system

MOV and X capacitor(s) as well as the differential surge voltage

specifications of the application.

As shown in Table 1, each device in the CAPZero family has a

825 V or 1000 V option. For applications where the system

MopOtiVoniswpilllatcyepdicianllpy opsriotivoidne1a(dMeOqVuPaOtSe1

in Figure 3), the 825 V

voltage withstand for

surge requirements up to 3 kV or more. The 1 kV CAPZero

would be recommended for higher surge requirements or if

additional voltage margin is required.

For MOV placement that is not directly across the X Capacitor1

(for example MOVPOS2 in Figure 3) the 1000 V CAPZero devices

can be used up to a surge specification of 1.5 kV. For differential

surge voltage specifications of >1.5 kV it is recommended that

the MOV is always placed in the location shown in Figure 3 as

MOVPOS1.

It is always recommended that the peak voltage between

terminals D1 and D2 of CAPZero is measured during surge

tests in the final system. Measurements of peak voltage across

CAPZero during surge tests should be made with oscilloscope

probes having appropriate voltage rating and using an isolated

supply to the oscilloscope to avoid ground currents influencing

measurement results. When making such measurements, it is

recommended that 50 V engineering margin is allowed below

the breakdown voltage specification (for example 950 V with the

1000 V CAPZero).

If the measured peak Drain voltage exceeds 950 V, an external

1 kV ceramic capacitor of value up to 47 pF can also be placed

between D1 and D2 terminals to attenuate the voltage applied

between the CAPZero terminals during surge. This optional

external capacitor placement is shown

should be noted that use of an external

acsaCpaEXcTitionr

Figure

in this

3. It

way

will

increase power consumption

discharge currents flowing in

slightly

R1 and

dRu2ewtohilteheACCEiXsT

charge/

connected.

A CEXT value of 33 pF will add approximately 0.5 mW at 230 VAC,

50 Hz.

PCB Layout and External Resistor Selection

Figure 4 shows a typical PCB layout configuration for CAPZero.

The external resistors in this case are divided into two separate

surface mount resistors to distribute loss under fault conditions

– for example where a short-circuit exists between CAPZero

terminals D1 and D2. R1 and R2 values are selected according

to Table 1.

Under a fault condition where CAPZero terminals D1 and D2 are

shorted together, each resistor will dissipate a power that can

be calculated from the applied AC voltage and the R1 and R2

values. For example in an application using CAP004 or CAP014,

R1=R2=390 kW. If CAPZero is shorted out at 265 VAC R1 and

R2 will each dissipate 45 mW.

Resistors R1 and R2 should also be rated for 50% of the system

input voltage again to allow for the short-circuitry of CAPZero

D1 to D2 pins during single point fault testing.

If lower dissipation or lower voltage across each resistor is

required during fault tests, the total external resistance can be

divided into more discrete resistors, however the total resistance

must be equal to that specified in Table 1.

www.powerint.com

3

Rev. D 11/11

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