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Primary Side PWM Controller
Features Description
The AS2214 is a full featured, pulse width modulation controller. Based on an improved AS3842, the AS2214 provides additional features that reduce component count and improve specifications in a wide range of power supply designs. The added functionality includes AC power and bulk voltage sensing, over-voltage input, as well as the ability to latch off or bounce through different fault conditions. The PWM function is controlled by the current sense comparator for normal current mode control and a second comparator for voltage mode soft start. A buffered RAMP signal is available for slope compensation without loading the oscillator. The output stage is a high current totem pole output that sees only 85 ns delay from the PWM comparator. The AS2214 requires less than 10A of startup current. The undervoltage lockout (UVLO) thresholds are nominally 13.8V for turn on and 8 V for turn off. A precision 2.5 V bandgap reference serves as an input for the error amplifier. The oscillator discharge current is trimmed to provide guaranteed duty cycle clamping.
AS2214
* * * * * * * * *
Low Startup Current Bulk and AC sensing Soft Start Single-start or auto-restart modes Oscillator trimmed for precision duty cycle clamp Standard temperature range extended to 105C Remote on / off control Buffered Ramp for slope compensation Standard current mode control
Pin Configuration --
Top view
VCC VREG COMP VFB ISNS SS RAMP 1 2 3 4 5 6 7 14 OUT 13 GND 12 BOK 11 LEN 10 ACP 9 8 OV RT/CT
Ordering Information
Package Temperature Range Order Code
14-Pin Plastic DIP
0 to 105 C
AS2214N
ASTEC Semiconductor
83
AS2214
Functional Block Diagram
Primary Side PWM Controller
VCC A CP AC DETECT (LEN) V REG 6V 5V enab le 5V Reg. V REG
LEN
50A UV LO
V REG BOK 2V 5 (BULK_UV ) 6A (CLR) 3V 95 OV (OV ) 2V 5 ISNS COMP SS LOGIC (RUN) SS
VFB 2V 5 2R CM PWM
VCC 1V R (PWM) OUT
SS PWM OSC (BLA NK)
RT/CT
GND
RA MP
x1
ASTEC Semiconductor
84
ENABL 0 1 1 1 1 0 1 Latch_bias 0 0 1 0 V REG 0 0 0 1 2V7 1 1 0 0 1 0 1 0 6A 0 1 0 1 V REG 0 0 Q *Q 0 0
AS2214 Soft Start Logic
Primary Side PWM Controller
ASTEC Semiconductor
Preset
S
R
Q
*Q
LEN ENBL OV S Q *Q S R ENBL S Q *Q ENBL S Q *Q R PRESET VOV R Started R VREG PRESET Faulted ENBL Q *Q PRESET
2V5
SS
85
PRESET
OV
1V7
3V9
BOK PWM_Disable
AS2214
2V5
AS2214
Pin Function Description
Pin Number Function
Primary Side PWM Controller
Description
1 2 3 4 5 6
VCC VREG COMP VFB ISNS SS
Positive supply voltage for the IC. Output of 5V series regulator. This pin is the error amplifier output. Typically used to provide loop compensation to maintain VFB at 2.5 V. Inverting input of the error amplifier. The non-inverting input is a trimmed 2.5 V bandgap reference. A voltage proportional to inductor current is connected to this pin. The PWM uses this information to terminate the gate drive of the output. This pin provides a 6A current source to linearly charge an external capacitor. This pin is compared to the RAMP pin in the soft start comparator, terminating output pulses when RAMP goes above the SS voltage. This pin is a level-shifted and buffered oscillator signal used to provide slope compensation to the current sense signal. The pin also serves as the non-inverting input of the softstart comparator. Oscillator frequency and maximum duty cycle are set by connecting a resistor (RT) to VREG and a capacitor (CT) to ground. This pin latches SS low when pulled above 2.5 V. The latch can be reset by pulling OV above 4 V then back to ground. This pin detects the presence of AC signal and drives LEN high. This pin must be high to enable starting. The pin can also clear all latches by going low then high. This pin monitors the bulk voltage through a resistor divider and, when BOK exceeds 2.5 V, provides a 50A current source for hysteresis. When BOK drops below 2.5V, SS is pulled low and the hysteresis current is turned off. Auto-restart after a brown-out is possible. Circuit common ground. This totem pole output is designed to directly drive a power MOSFET switch capable of sourcing and sinking peak currents up to 1 A.
7
RAMP
8 9 10 11 12
RT/CT OV ACP LEN BOK
13 14
GND OUT
ASTEC Semiconductor
86
Primary Side PWM Controller
Absolute Maximum Ratings
Parameter Symbol Rating
AS2214
Unit
Reference Current Output Current Supply Voltage Output Voltage Continuous Power Dissipation at 25 C Junction Temperature Storage Temperature Range Lead Temperature, Soldering 10 Seconds
IREF IOUT VCC VOUT PD TJ TSTG TL
200 1 20 20 500 150 - 65 to 150 300
mA A V V mW C C C
Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Recommended Conditions
Parameter Supply Voltage Oscillator Symbol VCC FOSC Rating 10 - 15 50 - 250 Unit V kHz
Typical Thermal Resistance
Package 14L PDIP JA 85 C/W JC 40 C/W Typical Derating 11.7 mW/C
Electrical Characteristics
Electrical Characteristics are guaranteed over full junction temperature range (0 to 105 C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. Unless otherwise specified, the conditions of test are VCC = 15 V; BOK = 3 V; OV = 0V; RT = 680 ; CT = 10 nF. To override UVLO, VCC should be raised above 18 V prior to test. Parameter Error Amplifier Input Voltage Input Bias Current Voltage Gain Transconductance Unity Gain Bandwidth Power Supply Rejection Ratio Output Sink Current Output Source Current Output Swing High Output Swing Low VFB IBIAS AVOL Gm GBW PSRR ICOMPL ICOMPH ICOMPH ICOMPL 12 VCC 18 V VFB = 2.7 V; VCOMP = 1.1 V VFB = 2.3 V; VCOMP = 5 V VFB = 2.3 V; RL = 15 to GND VFB = 2.7 V; RL = 15 to VREG 0.8 60 2 0.5 5 2 VCOMP 4 V 65 TJ = 25C 2.465 2.500 -0.1 90 1 1.2 70 6 1.0 5.5 0.7 1.1 2.535 -1 V A dB mA/mV MHz dB mA mA V V Symbol Test Condition Min Typ Max Unit
ASTEC Semiconductor
87
AS2214
Electrical Characteristics
(cont'd)
Primary Side PWM Controller
Electrical Characteristics are guaranteed over full junction temperature range (0 to 105 C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. Unless otherwise specified, the conditions of test are VCC = 15 V; BOK = 3 V; OV = 0V; RT = 680 ; CT = 10 nF. To override UVLO, VCC should be raised above 18 V prior to test. Parameter 5 V Regulator Output Voltage Line Regulation Load Regulation Temperature Stability Total Output Variation Long-Term Stability Output Noise Voltage Maximum Source Current Oscillator Initial Accuracy Voltage Stability Temperature Stability Amplitude Upper Trip Point Lower Trip Point Discharge Current Duty cycle Limit Over-Temperature Shutdown Soft Start Comparator SS Charge Current SS Discharge Current SS Lower Clamp RAMP High Level RAMP Low Level RAMP Levels TC ISS IDsc SS VSS Low VRAMPH VRAMPL TJ =25C TJ =25C Note: RAMP wavefrom is the same as the RT/CT wavefrom, but level shifted down one diode drop IRAMPL IRAMPH tPB TJ =25C TJ =25C - 0.1 1 85 150 VSS VRAMP VSS = 1 V, VOV > 2.5V -4 2 -6 8 0.6 2.15 0.6 -2 -10 A mA V V V mV/C TOT TCF VOSC VH VL IDSC RT =680 , CT =10nF, TJ =25C 7.50 46 FOSC TJ =25C 12 VCC 18 V TMIN TJ TMAX VRT/CT peak-to-peak 108 120 0.2 5 1.55 2.80 1.25 8.70 50 140 9.50 54 132 1 kHz % % V V V mA % C VNOISE IMAX TCREG Line, Load,Temperature Over 1,000 hrs at 25C 10 f 100kHz, TJ = 25C VREG = 4.8 V 30 4.85 5 50 120 180 VREG PSRR IREG = 1 mA, TJ= 25 C 12 VCC 18 V 1 IREG 20mA 4.90 5.00 5 5 0.2 5.10 15 15 0.4 5.15 25 V mV mV mV/C V mV V mA Symbol Test Condition Min Typ Max Unit
RAMP Sink Current RAMP Source Current Propagation Delay to Output
- 0.2
mA mA ns
ASTEC Semiconductor
88
Primary Side PWM Controller
Electrical Characteristics
(cont'd)
AS2214
Electrical Characteristics are guaranteed over full junction temperature range (0 to 105 C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. Unless otherwise specified, the conditions of test are VCC = 15 V; BOK = 3 V; OV = 0V; RT = 680 ; CT = 10 nF. To override UVLO, VCC should be raised above 18 V prior to test. Parameter Housekeeping BOK UV Threshold BOK UV Hysteresis Current BOK Input Bias Current OV Threshold OV Clear Threshold OV Reset Threshold OV Bias Current VBOK UV IHYST BOK IOFF BOK VOV VOVH VOVL IBIAS OV VREG = 5 V, VOV OV Threshold * For Vov > OV Reset Threshold, see characteristic curve IACP = 10 A IACP = -10 A IACP = 10 A; VLEN = 0 V IACP = -10 A; VLEN = 0 V -30 -30 VREG = 5 V VBOK = 2.6 V VBOK = 2.4 V 2.50 3.80 1.10 -1 2.500 42 2.537 50 0.1 2.80 4.00 1.75 -0.2 2.575 58 1.0 3.10 4.50 2.20 1 V A A V V V A Symbol Test Condition Min Typ Max Unit
ACP Voltage ACP Voltage LEN Charge Current LEN Charge Current Minimum Voltage for LEN Functionality LEN Logic Reset Voltage LEN Regeneration Current LEN Clamp LEN Bias Current
VACP VACP ILEN ILEN VLEN MIN VLEN ILENrgn VLEN IBIAS LEN
1.3 -1.2 -45 -50 3.6 -65 -65 4.5
V V A A V V A 6.6 V A
This level reflects one diode drop of hysteresis from VLEN min
3.0 -10
IACP = 5 A VLEN = 5 V, IACP = 0 A * For LEN input current over full range, see characteristic curve.
5.2
5.9 8
Current Sense Comparator Transfer Gain ISNS Level Shift Maximum Input Signal Power Supply Rejection Ratio Input Bias Current Propagation Delay to Output PSRR IBIAS tPB AVISNS VLS -0.2 VISNS 0.8 V VISNS = 0 V VCOMP =+5 V 12 VCC 18 V 1.00 2.85 3.00 1.50 1.08 70 -1 85 -10 150 1.20 3.15 V/V V V dB A ns
ASTEC Semiconductor
89
AS2214
Electrical Characteristics
(cont'd)
Primary Side PWM Controller
Electrical Characteristics are guaranteed over full junction temperature range (0 to 105 C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. Unless otherwise specified, the conditions of test are VCC = 15 V; BOK = 3 V; OV = 0V; RT = 680 ; CT = 10 nF. To override UVLO, VCC should be raised above 18 V prior to test. Parameter Under Voltage Lockout Startup Threshold Minimum Operating Voltage after Trun-on Startup Current Startup Current Operating Supply Current Maximum Operating Supply Voltage Output Impedance to GND in UVLO State Output Output Low Level Output Low Level Output High Level Output High Level Rise Time Fall Time Maximum Duty Cycle Minimum Duty Cycle VOL VOL VOH VOH tR tF DMAX DMIN ISINK = 20 mA ISINK = 150 mA ISOURCE = 20 mA ISOURCE = 150 mA CL = 1 nF CL = 1 nF 94 0 13 12 0.1 1.5 13.5 13 50 50 97 150 150 100 0.4 2.2 V V V V ns ns % % VCC (ON) VCC (OFF) ICC ICC ICC VCC Max ZOUT VCC = 6 V 22.0 VCC = 12 V; VACP = VLEN = 0 V VCC = 12V; IACP = 5 A 12.5 7.3 14.0 8.0 2 225 12 15.8 8.5 10 300 20 18 V V A A mA V k Symbol Test Condition Min Typ Max Unit
ASTEC reserves the right to make changes without further notice to any products described herein to improve reliability, function, or design. ASTEC does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights or the rights of others. ASTEC products are not authorized for use as components in life support devices or systems intended for surgical implant into the body or intended to support or sustain life. Buyer agrees to notify ASTEC of any such intended end use whereupon ASTEC will determine availability and suitability of its products for the intended use. ASTEC and the ASTEC logo are trademarks of ASTEC (BSR) PLC.
ASTEC SEMICONDUCTOR
255 Sinclair Frontage Road * Milpitas, California 95035 * Tel. (408) 263-8300 * FAX (408) 263-8340
ASTEC Semiconductor
90

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