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Supply Control IC with Critical Conduction Mode PFC andLLC Current-resonant Circuits

SSC4S911

PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

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Product Overview■Overview
The SSC4S911 is a power supply IC that integrates a CRM-driven PFC control circuit and an LLC current-resonant circuit in acompact SSOP24 package. The LLC stage includes high- and low-side drive circuits, which directly drive external power
MOSFETs in the half-bridge circuit. The PFC and LLC stages are highly interlocked in startup and standby operations, requiringno individual circuit settings. With extensive protections (e.g., the capacitive mode detection function), the SSC4S911 allows you
to easily design a high-safety, high-quality power supply system. In addition to such protections, the SSC4S911 has a startup
circuit that supports DC input, a function that enhances light-load efficiency, and more.

■Applications

・Audiovisual Equipment (e.g., LCD TV)
・Office Automation Equipment(e.g., Server, Multifunction Printer)・Communication Equipment
・Industrial Equipment

PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

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Product Features■Features■Package• PFC and LLC Stages Controlled by a Single IC
SSOP24• Interlocked PFC–LLC Stage Operations (Startup, Standby)• AC and DC Inputs Supported• X-capacitor Discharge (Enabled at AC Input, No Discharge ResistorRequired)• Burst Oscillation at Light Load (PFC and LLC Stages)• Critical Conduction Mode (CRM) PFC Control■Typical Application• PFC Maximum Oscillation Frequency Limitation• LLC Capacitive Mode Detection• LLC Soft Start• LLC Automatic Dead Time Adjustment• Protections- Input Voltage Protections (UVP, HVP)- PFC FB_PFC Pin Undervoltage Protection (FB_PFC_UVP)- PFC Output Overvoltage Protection (PFC_OVP)- PFC Overcurrent Protection (PFC_OCP)- LLC High-side Driver Undervoltage Lockout (VB_UVLO)- LLC Overcurrent Protection (LLC_OCP): Two Different Operations- LLC Overload Protection (LLC_OLP)- VCC Pin Overvoltage Protection (VCC_OVP)- Thermal Shutdown (TSD)

Pb-free (RoHS compliant)

D1

L1C1VAC

BR1C2

D2U1

R131STVGH

24

R142(NC)

VS23

R15R9R3VB

D9R6D6C9C10R10C11 R116VCC7PGND

89

SSC4S911

C7R7VSENC52 R53

R54
R56
R57 PS
ON/OFFU51 R55

R27

R58 C53
VOUT-C2122R21C65R26Q52

R12R5Q2

R25

R51

Q51

DLC5R8VOUT+R59

R52

D5D51

PC1C8C4R4R60

Q1

T2PC2DPR1R2

C51

T1C3D3D4PP

D52

Q3

R22

D7VGL

19

LGND

18

AGND

REG

17VG

RC

1610CSFB_LLC

1511ZCD

MC1412COMPFB_PFC

13

D8 R23

R24

C18C20C19R28PC2C12PC1R18

R19 C17
R20

R16PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

C22R17 C13 DZ1 C14 C15C163

Single-packaged PFC and LLC Stages■Component Count Substantially Reduced by Single Packaging
The SSC4S911 integrates the PFC and LLC stages into a single package.
As a result, component counts can be reduced by a large amount.*

Existing

SSC4S911

Individual control ICs are required for

Only a single control IC is required for

the PFC and LLC stages.

the PFC and LLC stages.

AC Input

PFC(CRM)

Half Bridge(LLC)

Down by 21 pcs

AC Input

PFC(CRM)

Half Bridge(LLC)

PFC–LLC interlocking parts: −7 pcs
IC-included adjustment parts: −5 pcs
Overlapping parts: −2 pcs
Other parts: −7 pcs* When compared with our own typical application.

PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

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Interlocked PFC–LLC Stage Operations■Interlocked Startup and Shutdown Operations
When the PFC stage output voltage reaches a given value atstartup, the LLC stage operation starts. This sequence
prevents startup failures. Once the IC detects a decrease in
the PFC stage output voltage, the LLC stage operation stops
before entering capacitive mode. This shutdown sequence
avoids hard switching caused by any capacitive mode
operation.
LLC PFC
OFF OFFPFC LLCON ON

PFC ON
LLC ONOFFOFF■Interlocked Standby Operation
In standby mode, both the PFC and LLC stages enter burst
oscillation operations to reduce switching losses. When the
LLC stage shifts to burst oscillation operation, so does the
PFC stage, allowing the IC to control the output voltage andreduce losses.
MC Pin Voltage
VMC(OFF)VMC(ON)

1.50 VVFB_LL C(ON )LLC Primary
Winding Current
LLC_ONVPFC

0FB_LLC Pin Voltage

VCC(ON)VCC(OFF)
VCC

Standby operation

LLC_OFF0

Burst oscillation0

VOUT(PFC)
0

VOUT
PFC
VG
LLC
VGL ( / VGH)FB_PFC Pin Voltage
90% VREF_PFC

89% VREF_PFC

VG Pin Voltage

0Burst oscillationt

PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

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Other Key Functions
1. Automatic Dead Time Adjustment Function
Detects a voltage-resonant period to automatically control thezero voltage switching (ZVS) operations of the high- and lowside power MOSFETs.
 Requires no dead timeadjustment

2. Standby Function
Performs the burst oscillation during the standby operation.
 Decreases the switching loss at light load

The soft-on/soft-off function prevents drain currents from varying
steeply during the burst oscillation. Controls switching frequencies
with the internal reference signal during the burst oscillation.
 Minimizes audible transformer noise

Waveforms at ZVS Failure

3. X-capacitor Discharge Function (AC Input Mode)
Requires no discharge resistor RDIS (IEC62368-1 compliant).
A typical line filter configuration needs RDIS that is connected toan X-capacitor in parallel and is always power-consuming.
 Increases circuit efficiencies

D1L1C1C2ISTR2C3C6

Typical Line Filter Circuit

PSE0074 Jul. 18, 2024

 Improves design-friendliness

AC Input Mode

VIN(AC)

BR1

D2

4. AC/DC Input Support
Determines whether the input voltage is AC or DC to enable theX-capacitor discharge function if AC and disable it if DC.

5R3

DC Input Mode

R11ST

U1VSENPGND AGND
87

RDIS removed; D1 , D2 , R1 connected to the ST pin.

SANKEN ELECTRIC CO., LTD.

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Physical Dimensions

0.20

3.9±0.10

1.90 (min.)

2.40±0.10+0.05-0.03

0 to 8°0.60

6.00±0.20■SSOP24

+0.20
-0.15

9.90±0.10

1.45±0.10

1.75 (max.)
0.80±0.10

PSE0074 Jul. 18, 2024

SANKEN ELECTRIC CO., LTD.

+0.10
0.25
-0.05

0.15±0.10
Unit: mm7

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PSE0074 Jul. 18, 2024

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