MP2A5100 - Fuji Electric - Datasheet.Directory

M-Power 2A Series of Multi-chip Power Devices 81

Takayuki Shimatoh

Noriho Terasawa

Hiroyuki Ota

M-Power 2A Series of Multi-chip

Power Devices

1. Introduction

Fuji Electric has developed highly efﬁ cient and

low-noise proprietary multi-oscillated current resonant

circuits for use in switching power supplies. As a cus-

tom device for this circuit, Fuji Electric has commer-

cialized the “M-Power 2”, housed in a small package

(SIP23) containing a control IC and two power MOS

FETs (metal oxide semiconductor ﬁ eld effect transis-

tors), and this device has been well received for use in

power supplies for ﬂ at panel televisions. As a result of

the trend toward increasingly larger sizes of ﬂ at panel

televisions in recent years, large capacity power sup-

plies (having an output power of approximately 400 W)

are being required. To support even larger capac-

ity power supplies, Fuji Electric has developed the M-

Power 2A series of devices provided with power MOS

FETs having a lower ON-resistance, and featuring im-

proved control IC functionality.

This paper introduces the M-Power 2 series and

the M-Power 2A series of multi-chip power devices, and

the operating principles of the multi-oscillated current

resonant power supply, to which these devices are ap-

plied.

2. Operating Principles of the Multi-oscillated

Current Resonant Converter

2.1 Circuit conﬁ guration

Figure 1 shows the basic circuit conﬁ guration of a

multi-oscillated current resonant converter in which

an M-Power 2 device is used. In the upper and lower

arms, the low-side switch Q1 (power MOSFET) is sepa-

rately-excited (PWM controlled) and is driven by a con-

trol IC and the high-side switch Q2 (power MOSFET)

is self-excited and is driven by an auxiliary winding

P2 of an isolated transformer Tr, and current resonant

operation is implemented with a series resonant circuit

consisting of the Tr leakage inductance and a resonant

capacitor Cr. P2 and the Vcc control winding P3, which

supplies power to the control IC, are designed to be

tightly coupled to P1, and each generates a voltage pro-

portional to the P1 voltage. However, the P2 voltage

has the reverse phase of the P1 voltage.

2.2 Basic operation

Figure 2 shows the operational timing chart.

During period (1), in the state where Q1 is ON and

Q2 is OFF, a current ﬂ ows through Cr to P1 and sup-

plies power to the load. Output voltage control is imple-

mented by feeding back to the control IC the signal

from the output voltage regulator circuit as a voltage

reference. The control IC compares the voltage refer-

ence to a reference signal value that increases in pro-

portion to the time elapsed since the zero-crossing of

VP1 (from negative to positive) and performs PWM con-

trol of Q1 so that the output voltage becomes constant.

During period (2), when Q1 turns OFF, the polar-

ity of VP1 inverts from positive to negative. Current

for charging the Q1 output capacitance and current for

discharging the Q2 output capacitance ﬂ ows from Tr,

and the Q1 drain voltage rises and the Q2 drain volt-

age drops.

During period (3), after the discharge is completed,

the Q2 body diode begins to conduct. At this timing,

ZVS (zero voltage switching) becomes active when Q2

turns ON. The gate voltage turn-on voltage is moder-

ated by a resistance connected to the Q2 gate terminal,

and the circuit is set such that ZVS will become active

and prevent Q1 and Q2 from both turning ON simulta-

Fig.1 Basic circuit conﬁ guration of the multi-oscillated current

resonant converter

Power 2

PWM control

Self-oscillator

Output voltage

regulator circuit

Normal/ standby signal

Control IC

IQ2

ID2

IQ1

ID1

VQ2

VG2

VQ1

VP1 VO

VG1

Rectifier or PFC

Vol. 53 No. 3

FUJI ELECTRIC REVIEW82

neously and a short-circuit current from ﬂ owing. Also,

with Q2 in an ON state, a current, inverted from that

of period (1), ﬂ ows to P1 and supplies power to the

load.

Operation during period (4) is the same as during

period (2). Afterwards, the operation returns to period

(1), and when discharging is completed, the Q1 body

diode begins to conduct. At this timing, ZVS becomes

active when Q1 turns ON. After the timing of the

negative to positive zero-crossing of VP1 is indirectly

detected by the P3 voltage, and after the time Td, dead

time for prevention of an arm short, has elapsed, Q1 is

turned ON.

2.3 Features

The converter has the following features.

(1) High efﬁ ciency

(2) Low noise

(3) No arm-short by lower frequency side operation

(the resonant breakaway phenomenon)

(4) High efﬁ ciency during light load operation

Features (1) and (2) above provide the same beneﬁ t

as the conventional current resonant circuit frequency

control method. However, features (3) and (4) are difﬁ -

cult to achieve with the frequency control method, and

a signiﬁ cant advantage of the present method is the

ability to provide these countermeasures and improve-

ments easily.

3. Overview of the M-Power 2A Series

Figure 3 shows the appearance of the M-Power 2

and M-Power 2A series devices. These devices use the

same package construction. The M-Power 2A series

features improved control IC functionality, and its pin

layout differs from that of the M-Power 2 series.

3.1 Structure

Internally, the M-Power 2A has an all-silicon

multi-chip conﬁ guration, and the M-Power 2A houses

a control IC and two power MOSFETs (Q1 and Q2) in

a SIP package having a height of 10 mm and width of

30 mm, which is suitable for application to low-proﬁ le

power supplies.

3.2 Control IC functions

The control IC, which was developed specially for

multi-oscillated control, has some general functions.

One is a computation function to control the PWM

(pulse width modulation) operation of the Q1 accord-

ing to the indicated value for the secondary side output

voltage. The other is a protection function by latched

shutdown against the overcurrent, load short-circuit,

overheat, overvoltage and undervoltage lockout. Also,

the latched shutdown function of the overcurrent pro-

tection and the overheat protection is provided with a

timer setting.

3.3 Power MOSFET

The power MOSFET used is a SuperFAP-G series

power MOSFET having the characteristics of low-re-

sistance and high switching speed, and aims to reduce

loss.

4. Improvements to the M-Power 2A and Differ-

ences from the M-Power 2 Series

The improvements to the M-Power 2A and differ-

ences from the M-Power 2 series are as listed below.

4.1 Structural improvements

Compared to the lead frame structure of the M-

Power 2, the M-Power 2A has a larger mounting area

for the power MOSFETs (Q1 and Q2), and enables

the mounting of power MOSFETs having lower ON-

Fig.3 Appearance of M-Power 2 and M-Power 2A series de-

vices

M-Power 2 series

M-Power 2A series

Fig.2 Operational timing chart

Voltage refer-

ence value,

Reference

signal value

Gate

threshold

voltage

Voltage reference value

Reference signal value

(1) (3)

(2) (4)

VP2

Dead time for prevention of arm short Td

VG2

VQ2 VQ1

VP3

VP1

ID1 ID2

IQ1 IQ2

VP2 , VG2

VQ1 , VQ2

VP1 , VP3

IQ1 , IQ2

ID1 , ID2

M-Power 2A Series of Multi-chip Power Devices 83

Table 1 Functional comparison of M-Power 2 and M-Power

Item M

Power 2

Input power

at standby

(when Po = 0 W)

Power 2A

0.6 W

(burst operation)

0.41 W

(burst operation)

Switching

restart timing

Minimum of

CB oscillation

FB voltage

reaches VthFB

Dead time for

prevention of

arm short

Fixed Adjustable

Circuit to prevent

audible noise at

light load

External circuit Built-in

Overvoltage

protection (OV) 1 shot latch Timer latch

at 270 μs

Overcurrent

protection (OC)

Plus detection

(+900 mV)

Minus detection

(

171 mV)

Short circuit

protection (SC)

Plus detection

(+1,500 mV)

1 shot latch

No function

Timer latch at 100 ms Timer latch at 36 ms

Built-in

standby mode

External

standby circuit

resistance (in order to ensure sufﬁ cient current capac-

ity, the provision of two main current terminals). As a

result, the MP2A5038 (500 V /0.38 Ω) is well suited for

application to output switching power supplies of ap-

proximately 400 W.

4.2 Control IC function and performance improvements

Table 1 compares the functions of the M-Power 2

and the M-Power 2A.

(1) Improved output voltage dropout characteristics

at sudden change in load

In the case of unloaded burst operation as shown in

Fig. 4 for a power supply equipped with an M-Power 2

device, if the load is suddenly changed to a near maxi-

mum loaded condition, a phenomenon occurs in which

the output voltage drops signiﬁ cantly. The voltage

drop occurs because after a sudden load change (from

no load to maximum load) during burst operation, even

if the output voltage reference value, COMP voltage

(FB (feedback) voltage in the case of the M-Power 2A),

rises, switching does not restart unless the CB (burst

operation frequency) oscillation reaches its lower limit.

Thus the M-Power 2A has been devised such that

switching restarts soon after the point in time when

the FB voltage rises, and therefore there is almost no

drop in output voltage, and a dramatic improvement is

realized.

(2) Surge voltage prevention of the overvoltage pro-

tection

The M-Power 2’s overvoltage protection operates to

instantaneously implement a latched shutdown when

an excessive voltage (overvoltage) is input. However,

it is desired that latched shutdown does not occur

for an overvoltage pulse having an extremely narrow

width, such as a lightening surge. Therefore, with the

M-Power 2A, the overvoltage protection function is pro-

vided with a 270 µs timer, and does not react to narrow

width overvoltage pulses.

(3) Less resistive loss for overcurrent protection detec-

tion

With the M-Power 2 series, overcurrent protection

circuit has an operating voltage of 900 mV, the current

detection resistance loss increases as the power supply

output power increases, and increasing the size of the

detection resistor results in greater heat generation.

On the other hand, the M-Power 2A has a lower operat-

ing voltage of 171 mV, and achieves reduced detection

resistance loss. The following improvements have been

made in the M-Power 2A.

(a) The current detection method has been

changed from plus to minus, and the inﬂ uence

of the power MOSFET’s drive current has been

eliminated.

(b) The current detection terminal is separated

from the power MOSFET’s source terminal,

and an externally attached ﬁ lter can be de-

signed freely in accordance with the power sup-

ply speciﬁ cations.

provided, the inﬂ uence of noise on the control

IC lessened, and the pattern layout has been

made easier to design.

(4) Built-in compensation circuit for light load burst

Fig.4 Schematic drawing of operation at sudden load change

Power 2

Power 2A

Delay time

COMP (M

Power 2)

FB (M

Power 2A)

CB (M

Power 2)

IO (load current)

VO (output voltage)

Power 2A)

VDS (Q1)

Power 2)

VDS (Q1)

Vcomp

VthFB

Power 2A

Vol. 53 No. 3

FUJI ELECTRIC REVIEW84

operation

With the M-Power 2, the operation is burst dur-

ing a light load, and in cases where an audible burst

operation sound from Tr creates a problem, it is recom-

mended that a circuit be attached externally to provide

a solution. On the other hand, with the M-Power 2A,

a compensation circuit for burst operation is built-in,

thereby enabling a reduction in the number of exter-

nally attached components.

(5) Reduced power consumption of control IC

The M-Power 2 has a built-in standby function, but

the M-Power 2A eliminates this function in order to

reduce the consumption of electrical power by the con-

trol IC. However, in the case where a standby function

is required in one converter, a standby function circuit

can be attached externally. (See Fig. 5.)

5. Conclusion

This paper has introduced the newly developed M-

Power 2A series of products that feature an improved

control IC for power supplies in ﬂ at panel televisions

and the like (Table 2). Accordingly, the M-Power 2A

series of devices are well suited for application to large

capacity power supplies for use in large screen ﬂ at

panel televisions and the like. In the future, Fuji Elec-

tric plans to expand the product lineup to support vari-

ous other requests. Fuji Electric also intends to strive

to develop power supply systems and to commercialize

custom power devices in order to support requests for

even more sophisticated power supplies.

Table 2 Fuji Electric’s M-Power 2A series product lineup

MOSFET

(Q1, Q2)

Model name Package

Control IC

500 V 16.5 V SIP23

125 to

150°C

VDS RDS (ON) VCC (ON) Tj (OFF)

MP2A5038 0.38 Ω

MP2A5050 0.50 Ω

MP2A5060 0.60 Ω

MP2A5077 0.77 Ω

MP2A5100 1.0 Ω

MP2A5135 1.35 Ω

Fig.5 External standby circuit

External

standby

circuit

PC2 PC1

PC1

VCC

Control

Regulator

VREF

CON

GND

Power 2A