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DATA SHEET
BiCMOS INTEGRATED CIRCUIT
PC1933
DC-DC CONVERTER CONTROL IC
DESCRIPTION
The PC1933 is an IC that controls a low-voltage input DC-DC converter. This IC is suitable for an operation with3-V, 3.3-V input or a lithium ion secondary battery input, because the minimum operating supply voltage is 2.5 V. Because of its wide operating voltage range, it can also be used to control DC-DC converters that use an AC adapter for input.
FEATURES
* Low supply voltage: 2.5 V (MIN.) * Operating voltage range: 2.5 to 20 V (breakdown voltage: 30 V) * Timer latch circuit for short-circuit protection. * Ceramic capacitor with low capacitance (0.1 F) can be used for short-circuit protection. * Open drain output (1 cannel: This output can be used to control a step-down converter, a step-up converter.) * Dead time is internally fixed to 85 %. * Soft start function (with a circuit to convert the timer latch circuit.)
ORDERING INFORMATION
Part Number Package 8-pin plastic SOP (5.72 mm (225))
PC1933GR
The information in this document is subject to change without notice. Before using this document, please confirm that this is the latest version.
Not all devices/types available in every country. Please check with local NEC representative for availability and additional information.
Document No. G13690EJ3V0DS00 (3rd edition) Date Published April 2000 NS CP (K) Printed in Japan
The mark 5 shows major revised points. 1998
PC1933
BLOCK DIAGRAM
FB 8 RT 7 GND 6 OUT 5
Oscillation section MOS input - + Internal fixed voltage Soft start select switch Timer latch for short-circuit protection section DTC (Internal fixed) Reference voltage section E/A PWM MOS output
- + +
1 II
2 DLY
3 VCC
4 VREF
2
Data Sheet G13690EJ3V0DS00
PC1933
PIN CONFIGURATION (Top View)
8-pin plastic SOP (5.72 mm (225)) * PC1933GR
II DLY VCC VREF
1 2 3 4
8 7 6 5
FB RT GND OUT
PIN FUNCTIONS
Pin No. 1 2 3 4 Symbol II DLY VCC VREF Function Error amplifier inverted input Short-circuit protection Power supply Reference voltage output Pin No. 5 6 7 8 Symbol OUT GND RT FB Function Open-drain output Ground Frequency setting resistor connection Error amplifier output
Data Sheet G13690EJ3V0DS00
3
PC1933
CONTENTS 1. ELECTRICAL SPECIFICATIONS ................................................................................................................ 5 2. CONFIGURATION AND OPERATION OF EACH BLOCK.................................................................... 11
2.1 Reference Voltage Generator ...........................................................................................................................11 2.2 Oscillator ...........................................................................................................................................................11 2.3 Under Voltage Lock-out Circuit ........................................................................................................................11 2.4 Error Amplifier...................................................................................................................................................11 2.5 PWM Comparator..............................................................................................................................................12 2.6 Timer Latch-Method Short Circuit Protection Circuit ....................................................................................12 2.7 Output Circuit....................................................................................................................................................12
3. NOTES ON USE........................................................................................................................................ 13
3.1 Setting the Output Voltage ...............................................................................................................................13 3.2 Setting the Oscillation Frequency ...................................................................................................................13 3.3 Preventing Malfunction of the Timer Latch-Method Short Circuit Protection Circuit..................................13 3.4 ON/OFF Control.................................................................................................................................................14 3.5 Maximum Duty Limit .........................................................................................................................................15 3.6 Notes on Actual Pattern Wiring........................................................................................................................15
4. APPLICATION EXAMPLE ......................................................................................................................... 16
4.1 Application Example.........................................................................................................................................16 4.2 List of External Parts ........................................................................................................................................16
5. PACKAGE DRAWING ................................................................................................................................ 17 6. RECOMMENDED SOLDERING CONDITIONS ....................................................................................... 18
4
Data Sheet G13690EJ3V0DS00
PC1933
1. ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings (unless otherwise specified, TA = 25 C)
Parameter Supply voltage Output voltage Output current (open drain output) Total power dissipation Operating ambient temperature Storage temperature Symbol VCC VO IO PT TA Tstg Ratings 30 30 21 480 -20 to + 85 -55 to + 150 Unit V V mA mW C C
Caution
Product quality may suffer if the absolute maximum rating is exceeded even momentarily for any parameter. That is, the absolute maximum ratings are rated values at which the product is on the verge of suffering physical damage, and therefore the product must be used under conditions that ensure that the absolute maximum ratings are not exceeded.
Recommended Operating Conditions
Parameter Supply voltage Output voltage Output current Operating temperature Oscillation frequency Symbol VCC VO IO TA fOSC -20 20 2.5 0 Ratings 20 20 20 +85 800 Unit V V mA C kHz
Caution
The recommended operating range may be exceeded without causing any problems provided that the absolute maximum ratings are not exceeded. However, if the device is operated in a way that exceeds the recommended operating conditions, the margin between the actual conditions of use and the absolute maximum ratings is small, and therefore thorough evaluation is necessary. The recommended operating conditions do not imply that the device can be used with all values at their maximum values.
Data Sheet G13690EJ3V0DS00
5
PC1933
Electrical Characteristics (unless otherwise specified, TA = 25 C, VCC = 3 V, fOSC = 100 kHz)
Block Under voltage Lock-out section Reference Voltage section Parameter Start-up voltage Operation stop voltage Hysteresis voltage Reset voltage (timer latch) Reference voltage Line regulation Load regulation Temperature coefficient Oscillation section fOSC setting accuracy fOSC total stability Symbol VCC (L-H) VCC (H-L) VH VCCR VREF REGIN REGL VREF/T fOSC fOSC Conditions IREF = 0.1 mA IREF = 0.1 mA IREF = 0.1 mA IREF = 0.1 mA IREF = 1 mA 2.5 VVCC20 V 0.1 mAIREF1 mA -20 CTA+85 C, IREF = 0 A RT = 18 k -20 CTA+85 C, 2.5 VVCC20 V PWM comparator section Error Amplifier section Soft start time Input threshold voltage Input bias current Open loop gain Unity gain Maximum output voltage (+) Maximum output voltage (-) Output sink current Output source current Output section Drain cutoff current Output ON voltage Rise time Fall time Short-circuit Protection section Input sense voltage UV sense voltage Source current on short-circuiting Delay time Overall Circuit operation current tSS VITH IB Av funity VOM VOM
+ -
MIN.
TYP. 1.57 1.5
MAX.
Unit V V mV V
30
70 1.0
2.0
2.1 2 2 0.5
2.2 12.5 7.5
V mV mV %
-20 -20
+30 +50
% %
Maximum duty
DMAX. CDLY = 0.1 F 0.285 -100 VO = 0.3 V VO = 0.3 V IO = -45 A IO = 45 A VFB = 0.5 V VFB = 1.6 V VO = 30 V RL = 150 RL = 150 RL = 150 1.75 0.8 1.6 70
85 50 0.3 0.315 +100 80 1.5 2 0.02 1.4 -70 -45 100 0.2 50 60 1.92 0.8 1.0 CDLY = 0.1 F VCC = 3 V 1.4 1.6 50 2.6 3.9 2.05 0.85 2.7 0.6 0.5
% ms V nA dB MHz V V mA
IOsink IOsource ILEAK VOL tr tf VTH VUV IOUV tDLY ICC
A A
V ns ns V V
A
ms mA
Caution Connect a capacitor of 0.01 to 10 F to the VREF pin.
4
PC1933
6
CREF = 0.01 to 10 F
6
Data Sheet G13690EJ3V0DS00
Timing Chart
Soft start by CDLY Detected finishing of soft- start, Switch DTC (internal fixed)
Soft start by CDLY Voltage of FB pin
Short-load
Pin voltage
Voltage of DLY pin Voltage of DLY pin
Data Sheet G13690EJ3V0DS00
OUT OFF ON Output oscillation is stopped
PC1933
7
PC1933
Typical Characteristic Curves (unless otherwise specified, VCC = 3 V, fOSC = 100 kHz, TA = 25 C) (Nominal)
PT vs TA 0.5 2.5 IREF = 0 A 0.4 260.4 C/W 0.3 VREF vs VCC
Total power dissipation PT (W)
Reference voltage VREF (V)
2.0
1.5
0.2 0.1
1.0 0.5
0
25 50 75 100 125 150 Operating ambient temperature TA (C) VREF vs TA
0
1 2 3 4 Supply voltage VCC (V) fOSC vs RT
5
2.13 IREF = 0 A
1000
Reference voltage VREF (V)
2.12 2.11 2.10 2.09 2.08 2.07 -25 0 25 50 75 100 Operating ambient temperature TA (C) fOSC vs TA
Oscillation frequency fOSC (kHz)
100
10
1
10 Timing resistance RT (k) VOL vs IO
100
Oscillation frequency accuracy fOSC (%)
6 RT = 18 k
0.5
Output ON voltage VOL (V)
4 2 0 -2 -4 -6 -25 0 25 50 75 100 Operating ambient temperature TA (C)
0.4
0.3
0.2 0.1
0
5 10 15 Output current IO (mA)
20
8
Data Sheet G13690EJ3V0DS00
PC1933
VOL vs TA 0.4
Channel maximum duty DMAX. (%)
DMAX. vs RT 100
IO = 20 mA
Output ON voltage VOL (V)
0.3
90 80
0.2
70
0.1
60 50
0 -25
0
25
50
75
100
1
10 Timing resistance RT (k)
100
Operating ambient temperature TA (C)
Short-circuit protection circuit delay time tDLY (ms)
tSS vs CDLY 600
Channel soft start time tSS (ms)
tDLY vs CDLY 600 500 400 300 200 100
500 400 300 200 100
0
0.2
0.4
0.6
0.8
1.0
0
0.2
0.4
0.3
0.4
1.0
DLY pin capacitor capacitance CDLY ( F)
DLY pin capacitor capacitance CDLY ( F)
tDLY vs TA 60 50
Delay time tDLY (ms)
Av, vs f 100 80 60 40 Av 20 0 0 -45 -90 10 M
180 135
Phase (deg)
Gain Av (dB)
40 30 20 10 CDLY = 0.1 F 0 -25 0 25 50 75 100
90 45
-20 100
1k
10 k
100 k
1M
Operating ambient temperature TA (C)
Frequency f (Hz)
Data Sheet G13690EJ3V0DS00
9
PC1933
ICC vs VCC 3
Circuit operation ICC (mA) Circuit operation ICC (mA)
ICC vs TA 4
3
2
2
1
1
0
5
10 15 20 25 Supply voltage VCC (V)
30
0 -25 0 25 50 75 100 Operating ambient temperature TA (C)
10
Data Sheet G13690EJ3V0DS00
PC1933
2. CONFIGURATION AND OPERATION OF EACH BLOCK
Figure 2-1 Block Diagram
Oscillation section FB II 8 1 Error amplifier 0.3 V PWM comparator VREF 4 Under voltage lock-out section
7
RT
5
OUT
Output section
VCC
3
Reference voltage section
Dead time setting: 85 % (internally fixed)
SCP comparator Q1 1.92 V Q2
S
Q 6 Q GND
DLY
Soft start select switch 2 CDLY
Timer latch for short-circuit protection section
2.1
Reference Voltage Generator
The reference voltage generator is comprised of a band-gap reference circuit, and outputs a temperature-compensated reference voltage (2.1 V). The reference voltage can be used as the power supply for internal circuits, or as a reference voltage, and can also be accessed externally via the VREF pin (pin 4).
2.2
Oscillator
The oscillator self-oscillates if a timing resistor is attached to the RT pin (pin 7). This oscillator waveform is input to the inverted input pin of the PWM comparator to determine the oscillation frequency.
2.3
Under Voltage Lock-out Circuit
The under voltage lock-out circuit prevents malfunctioning of the internal circuits when the supply voltage is low, such as when the supply voltage is first applied, or when the power supply is interrupted. When the voltage is low, the output transistor is cut off at the same time.
2.4
Error Amplifier
The non-inverted input pin of the error amplifier is connected internally to 0.3 V (the input threshold voltage is 0.3 V (TYP The first stage of the error amplifier is a P-channel MOS transistor input. .)).
Data Sheet G13690EJ3V0DS00
11
PC1933
2.5 PWM Comparator
The output ON duty is controlled according to the outputs of the error amplifier. A triangular waveform is input to the inverted pin, and the error amplifier output and Dead Time Control pin voltage (fixed internally) are input to the non-inverted pins of the PWM comparator. Therefore, the output transistor ON period is the period when the triangular waveform is lower than the error amplifier output and Dead Time Control pin voltage (fixed internally) (refer to Timing Chart).
2.6
Timer Latch-Method Short Circuit Protection Circuit
When the output of the converter drops, the non-inverted input pin (1 pin) voltage of the error amplifier drops, and the FB output of the error amplifier of the output goes high. If the FB output exceeds the timer latch input detection voltage (VTH = 1.92 V), then the output of the SCP comparator goes low, and Q1 goes off. When Q1 turns OFF, the constant-current supply charges CDLY via the DLY pin. The DLY pin is internally connected to a flip-flop. When the DLY pin voltage reaches the UV detection voltage (VUV = 0.7 V (TYP the output Q of the flip-flop goes .)), low, and the output stage is latched to OFF (refer to Figure 2-1 Block Diagram). Make the power supply voltage briefly less than the reset voltage (VCCR, 1.0 V TYP to reset the latch circuit when the .) short-circuit protection circuit has operated.
2.7
Output Circuit
The output circuit has an N-channel open-drain output providing an output withstand voltage of 30 V (absolute maximum rating), and an output current of 21 mA (absolute maximum rating).
12
Data Sheet G13690EJ3V0DS00
PC1933
3. NOTES ON USE
3.1
Setting the Output Voltage
Figure 3-1 illustrates the method of setting the output voltage. The output voltage is obtained using the formula shown in the figure. The input threshold value of the error amplifier is 0.3 V (TYP for the error amplifier. Therefore, select a resistor value .) that gives this voltage.
Figure 3-1 Setting the Output Voltage
VOUT (positive voltage)
VOUT = 1 +
R1 * 0.3 R2
R1 1 R2 CNF RNF 8 0.3 V E/A
3.2
Setting the Oscillation Frequency
Choose RT according to the oscillation frequency (fOSC) vs timing resistor (RT) characteristics (refer to Typical Characteristics Curves fOSC vs RT.) The formula below (3-1) gives an approximation of fOSC. However, the result of formula 3-1 is only an approximation, and the value must be confirmed in actual operation, especially for high-frequency operation.
fOSC[Hz] 1.856 x 10 /RT[]
9
(3-1)
3.3
Preventing Malfunction of the Timer Latch-Method Short Circuit Protection Circuit
The timer latch short-circuit protection circuit operates when the error amplifier output (pin 8) exceed approximately 1.92 V, and cuts off the output. However, if the rise of the power supply voltage is fast, or if there is noise on the DLY pin (pin 2), the latch circuit may malfunction and cut the output off. To prevent this, lower the wiring impedance between the DLY pin and the GND pin (pin 6), and avoid applying noise to the DLY pin.
Data Sheet G13690EJ3V0DS00
13
PC1933
3.4 ON/OFF Control
The ON/OFF control method of the output oscillation is to input the ON/OFF signal from ON as shown in Figure 3-2. Soft start or timer latch (SCP) is internally selected. Soft start is executed when the first start signal is input. When the end of soft start is detected, the soft start select switch is turned OFF and the timer latch circuit operates.
Figure 3-2 ON/OFF Control
VO (Converter output voltage)
R1 II
-
FB SCP comparator
+ -
R2
+
Error amplifier
Q
0.3 V D1 Dead time setting: 85 % (internally fixed) VREF R
+ + -
0.63 V
To output stage PWM comparator
ON
Q1 CDLY DLY
SW
Oscillation section (common to each channel)
(1) When ON is high: OFF status Q1: ON DLY pin: Low level Output duty of PWM comparator: 0 % D1: ON II pin: High level FB output: Low level
(2) When ON is low: ON status (start up) Q1: OFF CDLY is charged in the sequence of [VREF R1 SW DLY pin CDLY] Soft start D1: OFF II pin: Low level FB output: High level
(3) When ON goes high again after start up (SW: OFF): OFF status Q1: ON DLY pin: Low level (Nothing happens because SW is OFF.) D1: ON II pin: High level FB output: Low level PWM comparator output duty: 0 % Converter output voltage (VO) drops.
Caution Even if start up is executed by making ON low again after (3), soft start is not executed because the soft start select switch (SW) remains OFF. To execute soft start again, drop VCC to 0 V once.
14
Data Sheet G13690EJ3V0DS00
PC1933
3.5 Maximum Duty Limit
PC1933 is switched internally between Soft Start and Timer Latch. For this reason, the DTC voltage is fixed internally,
and the maximum duty is limited to 85%.
3.6
Notes on Actual Pattern Wiring
When actually carrying out the pattern wiring, it is necessary to separate control-related grounds and power-related grounds, and make sure that they do not share impedances as far as possible. In addition, make sure the high-frequency impedance is lowered using capacitors and other components to prevent noise input to the VREF pin.
Data Sheet G13690EJ3V0DS00
15
PC1933
4. APPLICATION EXAMPLE
4.1
Application Example
Figure 4-1 shows an example circuit for obtaining +5 V/50 mA from a +3 V power supply.
Figure 4-1 Application Example
COM VIN = 3 V
C5 1 F R2 47 k RT 3.9 k R5 150
R6 470 Q1 C2 100 pF R8 7.5 k
L1 47 H R9 68 Q3
D1
VO = + 5 V IO = 50 mA
8
FB C1 3300 pF R1 30 k II
7
6
5
RT GND OUT
R7 R3 20 k 2.4 k VR4 1 k
C3 100 pF Q2 R10 20 k
C4 68 F
PC1933
DLY VCC VREF
COM
1
2
3
CDLY 0.1 F
4
C0 0.1 F
4.2
List of External Parts
The list below shows the external parts.
Table 4-1 List of External Parts
Symbol C4 D1 L1 Q3 Q1 Q2 47 H Parameter 68 F Function Output capacitor Schottkey diode Choke inductor Switching transistor Buffer transistor Buffer transistor Part number 20SA68M D1FS4 636FY-470M 2SD2403 2SC1623 2SA812 Maker SANYO SHINDENGEN TOKO NEC NEC NEC D73F series Remark OS-CON, SA series
Remarks 1. The capacitors that are not specified in the above list are multilayer ceramic capacitors. 2. The resistors that are not specified in the above list are 1/4W resistors.
16
Data Sheet G13690EJ3V0DS00
PC1933
5. PACKAGE DRAWING
8-PIN PLASTIC SOP (5.72 mm (225))
8 5
detail of lead end
P
1 A
4
H F G I J
S B C D E
NOTE Each lead centerline is located within 0.12 mm of its true position (T.P.) at maximum material condition.
ITEM A B C D E F G H I J K L M N P MILLIMETERS 5.2 +0.17 -0.20 0.78 MAX. 1.27 (T.P.) 0.42 +0.08 -0.07 0.10.1 1.590.21 1.49 6.50.3 4.40.15 1.10.2 0.17 +0.08 -0.07 0.60.2 0.12 0.10 +7 3 -3 S8GM-50-225B-6
L K N S
M
M
Data Sheet G13690EJ3V0DS00
17
PC1933
6. RECOMMENDED SOLDERING CONDITIONS
Recommended solder conditions for this product are described below. For details on recommended soldering conditions, refer to Information Document "Semiconductor Device Mounting Technology Manual" (C10535E). For soldering methods and conditions other than those recommended, consult NEC.
Surface Mount Type
PC1933GR: 8-pin plastic SOP (5.72 mm (225))
Soldering Method Soldering Conditions Symbol of Recommended Conditions Infrared reflow Package peak temperature: 235 C, Time: 30 seconds MAX. (210 C MIN.), Number of times: 3 MAX. VPS Package peak temperature: 215 C, Time: 40 seconds MAX. (200 C MIN.), Number of times: 3 MAX. Wave soldering Soldering bath temperature: 260 C MAX., Time: 10 seconds MAX., Number of times: 1, Preheating temperature: 120 C MAX. (package surface temperature) WS60-00-1 VP15-00-3 IR35-00-3
Caution Do not use two or more soldering methods in combination.
18
Data Sheet G13690EJ3V0DS00
PC1933
NOTES FOR BiCMOS DEVICES
1 PRECAUTION AGAINST ESD FOR SEMICONDUCTORS Note:
Strong electric field, when exposed to a device, can cause destruction of the gate oxide and ultimately degrade the device operation. Steps must be taken to stop generation of static electricity as much as possible, and quickly dissipate it once, when it has occurred. Environmental control
must be adequate. When it is dry, humidifier should be used. It is recommended to avoid using insulators that easily build static electricity. Semiconductor devices must be stored and transported in an anti-static container, static shielding bag or conductive material. All test and measurement tools including work bench and floor should be grounded. The operator should be grounded using wrist strap. Semiconductor devices must not be touched with bare hands. Similar precautions need to be taken for PW boards with semiconductor devices on it. 2 HANDLING OF UNUSED INPUT PINS Note:
No connection for device inputs can be cause of malfunction. If no connection is provided to the input pins, it is possible that an internal input level may be generated due to noise, etc., hence causing malfunction. Input levels of devices must be fixed high or low by using a pull-up or pulldown circuitry. Each unused pin should be connected to VDD or GND with a resistor, if it is considered to have a possibility of being an output pin. All handling related to the unused pins must be judged device by device and related specifications governing the devices.
3
STATUS BEFORE INITIALIZATION OF BiCMOS DEVICES Note:
Power-on does not necessarily define initial status of device. Production process of BiCMOS does not define the initial operation status of the device. Immediately after the power source is turned ON, the devices with reset function have not yet been initialized. Hence, power-on does not guarantee out-pin levels, I/O settings or contents of registers. Device is not initialized until the reset signal is received. Reset operation must be executed immediately after power-on for devices having reset function.
Data Sheet G13690EJ3V0DS00
19
PC1933
[MEMO]
* The information in this document is subject to change without notice. Before using this document, please confirm that this is the latest version. * No part of this document may be copied or reproduced in any form or by any means without the prior written consent of NEC Corporation. NEC Corporation assumes no responsibility for any errors which may appear in this document. * NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual property rights of third parties by or arising from use of a device described herein or any other liability arising from use of such device. No license, either express, implied or otherwise, is granted under any patents, copyrights or other intellectual property rights of NEC Corporation or others. * Descriptions of circuits, software, and other related information in this document are provided for illustrative purposes in semiconductor product operation and application examples. The incorporation of these circuits, software, and information in the design of the customer's equipment shall be done under the full responsibility of the customer. NEC Corporation assumes no responsibility for any losses incurred by the customer or third parties arising from the use of these circuits, software, and information. * While NEC Corporation has been making continuous effort to enhance the reliability of its semiconductor devices, the possibility of defects cannot be eliminated entirely. To minimize risks of damage or injury to persons or property arising from a defect in an NEC semiconductor device, customers must incorporate sufficient safety measures in its design, such as redundancy, fire-containment, and anti-failure features. * NEC devices are classified into the following three quality grades: "Standard", "Special", and "Specific". The Specific quality grade applies only to devices developed based on a customer designated "quality assurance program" for a specific application. The recommended applications of a device depend on its quality grade, as indicated below. Customers must check the quality grade of each device before using it in a particular application. Standard: Computers, office equipment, communications equipment, test and measurement equipment, audio and visual equipment, home electronic appliances, machine tools, personal electronic equipment and industrial robots Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster systems, anti-crime systems, safety equipment and medical equipment (not specifically designed for life support) Specific: Aircraft, aerospace equipment, submersible repeaters, nuclear reactor control systems, life support systems or medical equipment for life support, etc. The quality grade of NEC devices is "Standard" unless otherwise specified in NEC's Data Sheets or Data Books. If customers intend to use NEC devices for applications other than those specified for Standard quality grade, they should contact an NEC sales representative in advance.
M7 98. 8

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