TS19701A
CC/CV Primary-Side PWM Controller
SOT-26
Pin Definition:
1. GND
2. Gate
3. Current Sense
4. INV
5. Compensation
6. VDD
Description
TS19701A is a high performance offline PWM Power switch for low power AC/DC charger and adapter
applications. It operates in primary-side sensing and regulation. Consequently, opto-coupler and TS431 could be
eliminated. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated as shown in the
figure below. In CC control, the current and output power setting can be adjusted externally by the sense resistor
Rs at CS pin. In CV control, multi-mode operations are utilized to achieve high performance and high efficiency. In
addition, good load regulation is achieved by the built-in cable drop compensation. Device operates in PFM in CC
mode as well at large load condition and it operates in PWM with frequency reduction at light/medium load.
TS19701A offers power on soft start control and protection coverage with auto-recovery features including Cycle-
by- Cycle current limiting, VDD OVP, VDD clamp and UVLO. Excellent EMI performance is achieved with Power-
Source proprietary frequency shuffling technique. High precision constant voltage (CV) and constant current (CC)
can be achieved by TS19701A
Features
●
●
●
●
●
●
●
●
●
●
●
±5%
Constant Voltage Regulation at Universal AC
input
Primary-side Sensing and Regulation
Programmable CV and CC Regulation
Adjustable Constant Current and Output Power
Setting
Built-in Adaptive Current Peak Regulation
Built-in Primary winding inductance compensation
Programmable Cable drop Compensation
Power on Soft-start
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis
Application
●
●
LED lighting
Cell phone charger
Ordering Information
Part No.
TS19701ACX6 RFG
Package
SOT-26
Packing
3Kpcs / 7” Reel
Note:
“G” denote for Halogen Free Product
Absolute Maximum Rating
(Ta = 25
o
C unless otherwise noted)
Characteristics
Drain Voltage (off state)
VDD Voltage
VDD Zener Clamp Continuous Current
COMP Voltage
CS Input Voltage
INV Input Voltage
Max Operating Junction Temperature
Min/Max Storage Temperature
Thermal Resistance from Junction to case
Thermal Resistance from Junction to ambient
Symbol
V
DRAIN
V
DD
--
V
COMP
V
CS
V
INV
TJ
T
STG
θ
JC
θ
JA
Rating
-0.3 to Bvdss
-0.3 to VDD_Clamp
10
-0.3 to 7
-0.3 to 7
-0.3 to 7
150
-55 to 150
180
250
Unit
V
V
mA
V
V
V
°
C
°
C
°
C/W
°
C/W
1/9
Version: A12
TS19701A
CC/CV Primary-Side PWM Controller
Electrical Specifications
(Ta = 25
o
C unless otherwise noted)
Characteristics
Supply Voltage (VDD) Section
Standby Current
Operation Current
VDD Under Voltage Lockout Enter
VDD Under Voltage Lockout Exit
Maximum VDD operation voltage
Over Voltage protection voltage
Current Sense Input Section
LEB time
Over current threshold
OCP Propagation delay
Input Impedance
Soft start time
Frequency Section
IC Maximum frequency
System Nominal switch frequency
Frequency shuffling range
Error Amplifier section
Reference voltage for EA
DC gain of EA
Max. Cable compensation current
Vref_EA
Gain
I_COMP_MA
X
I
NV
=2V, Comp=0V
1.97
-
-
2
60
37.5
2.03
-
-
V
dB
uA
Freq_Max
Freq_Nom
Freq_startup
∆f/Freq
I
NV
=0V, Comp=5V
(Note)
55
--
--
--
60
50
14
+/-6
65
--
--
--
KHZ
KHZ
KHZ
%
T
LEB
Vth_oc
Td_oc
Z
SENSE
_IN
T_
SS
--
880
--
50
--
625
910
110
--
17
--
940
--
--
--
Ns
mV
Ns
KΩ
ms
I
DD ST
I
DD OP
U
VLO(ON)
U
VLO(OFF)
V
DD
clamp
OVP
V
DD
=13V
Operation supply current
I
NV
=2V, C
S
=0V,
V
DD
=V
DDG
=18V
V
DD
falling
V
DD
rising
I
DD
=10mA
Ramp V
DD
until gate shut
down
8.2
13.5
27
26
9.0
14.8
28.5
27.5
10.5
16.0
30
29
V
V
V
V
--
2
3
mA
--
5
20
uA
Symbol
Conditions
Min
Typ
Max
Units
Note:
Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation
frequency of 60Khz nominal occurs at maximum output power or the transition point from CV to CC
2/9
Version: A12
TS19701A
CC/CV Primary-Side PWM Controller
Typical Application Circuit
Block Diagram
Pin Description
Pin
1
2
3
4
5
6
Function
GND
Gate
CS
INV
COMP
VDD
Description
Ground
Drive MOSFET
Current sense input
The voltage feedback from auxiliary winding
Loop Compensation for CV Stability
Power Supply
3/9
Version: A12
TS19701A
CC/CV Primary-Side PWM Controller
Function Description
TS19701A is a cost effective PWM power switch optimized for off-line low power AC/DC applications including
battery chargers and adapters. It operates in primary side sensing and regulation, thus opto-coupler and TL431 are
not required. Proprietary built-in CV and CC control can achieve high precision CC/CV control meeting most
adapter and charger application requirements.
Startup Current and Start up Control
Startup current of TS19701A is designed to be very low so that VDD could be charged up above UVLO threshold
and starts up quickly. A large value startup resistor can therefore be used to minimize the power loss in application.
Operating Current
The Operating current of TS19701A is as low as 2.0mA. Good efficiency is achieved with the low operating current
together with ‘Muti-mode’ control features.
Soft Start
TS19701A features an internal soft start to minimize the component electrical over-stress during power on startup.
As soon as VDD reaches UVLO (OFF), the control algorithm will ramp peak current voltage threshold gradually
from nearly zero to normal setting of 0.91V. Every restart is a soft start.
CC/CV Operation
TS19701A is designed to produce good CC/CV control characteristic as shown in the Fig. 1. In charger
applications, a discharged battery charging starts in the CC portion of the curve until it is nearly full charged and
smoothly switches to operate in CV portion of the curve. In an AC/DC adapter, the normal operation occurs only on
the CV portion of the curve. The CC portion provides output current limiting. In CV operation, the output voltage is
regulated through the primary side control. In CC operation mode, TS19701A will regulate the output current
constant regardless of the output voltage drop.
Principle of Operation
To support TS19701A proprietary CC/CV control, system needs to be designed in DCM mode for flyback system
(Refer to Typical Application Diagram on page1). In the DCM flyback converter, the output voltage can be sensed
via the auxiliary winding. During MOSFET turn-on time, the load current is supplied from the output filter capacitor
Co. The current in the primary winding ramps up. When MOSFET turns off, the primary current transfers to the
secondary at the amplitude of
The auxiliary voltage reflects the output voltage as shown in fig.2 and it is given by
Where
∆V
indicates the drop voltage of the output Diode.
4/9
Version: A12
TS19701A
CC/CV Primary-Side PWM Controller
Function Description (Continue)
Fig.2. Auxiliary voltage waveform
Via a resistor divider connected between the auxiliary winding and INV (pin 4), the auxiliary voltage is Sampled at
the end of the demagnetization and it is hold until the next sampling. The sampled voltage is compared with Vref
(2.0V) and the error is amplified. The error amplifier output COMP reflects the load condition and controls the PWM
switching frequency to regulate the output voltage, thus constant output voltage can be achieved. When sampled
voltage is below Vref and the error amplifier output COMP reaches its maximum, the switching frequency is
controlled by the sampled voltage thus the output voltage to regulate the output current, thus the constant output
current can be achieved.
Adjustable CC point and Output Power
In TS19701A, the CC point and maximum output power can be externally adjusted by external current sense
resistor Rs at CS pin as illustrated in Typical Application Diagram. The output power is adjusted through CC point
change. The larger Rs, the smaller CC point is, and the smaller output power becomes, and vice versa as shown in
Fig.3
Fig.3 Adjustable output power by changing Rs
5/9
Version: A12
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