NJM2344. PWM DC/DC Converter IC with Standby Function FEATURES

Transcription

1 PWM DC/DC Converter IC with Standby Function GENERAL DESCRIPTION The NJM344 is a general purpose PWM DC/DC converter IC configurable for step-up, step-down and inverting applications. An internal.a power transistor, a pulse-by pulse current limit and % precision reference make the NJM344 suitable for a wide range of voltage converter needs. The NJM344 features a standby function that can be used for both power saving and safety operation. PACKAGE OUTLINE NJM344D NJM344M FEATURES Operating Voltage 3.V to 4V Wide Oscillator Frequency khz to khz Precision Reference Voltage V th =.V ± % Internal High Power Transistor.A max. Internal Over Current Limit Circuit PWM switching control Standby Function 9µA typ. Bipolar Technology Package Outline NJM344D : DIP NJM344M : DMP PIN CONFIGURATION BLOCK DIAGRAM 3 4 NJM344D NJM344M PIN FUNCTION. C S. E S GND. IN-. V +.. S I C S E S CT 3.A Ω OSC Block MAX ON Duty 9: Q R PWM Logic Ipk Sense S 3mV S I High :ON Low :OFF (Standby) V + Vref.V Error AMP PWM COMP GND 4 IN- Buffer Ver

2 ABSOLUTE MAXIMUM RATINGS (Ta= C) PARAMETER SYMBOL MAXIMUM RATINGS UNIT Maximum Supply Voltage V + 4 V Comparator Input Voltage V IR -.3 ~ 4 (note) V Terminal Voltage V -.3 ~ 4 (note) Output Switch Voltage V SW 4 V Output Switch Current I SW. A Power Dissipation P D DIP DMP (*) (*) mw Operating Temperature Range Topr -4 ~ + C Storage Temperature Range Tstg - ~ + C (note) When supply voltage is less than 4V, the absolute maximum input voltage is equal to the supply voltage. (*) At on PC board : 4.3mm.mm.mm( layer FR-4) : Conform to EIA/JEDEC (*) At on PC board : 4.3mm.mm.mm(4 layer FR-4) : Conform to EIA/JEDEC POWER DISSIPATION vs. AMBIENT TEMPERATURE Power Dissipation P D (mw) Power Dissipation vs. Ambient Temperature (Topr=-4~+ o C, Tj= ~ o C) 4 DIP DMP At on 4 layer PC Board At on layer PC Board ELECTRICAL CHARACTERISTICS - - Ver.9--

3 DC Characteristics (V + = V=V, Ta= C) PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT OSCILLATOR BLOCK Oscillation Frequency f OS-=V, =nf 3 khz Charge Current I chg µa Discharge Current I dis 3 µa Voltage Swing V OSC =nf. V P-P Discharge to Charge Current Ratio I ratio I chg /I dis 9 CURRENT LIMIT Peak Current Sense Voltage V ipk I chg =I dis 3 3 mv OUTPUT SWITCH Saturation Voltage V sat I SW =.A..3 V Output Transistor Bias Resistance R bias Ω Collector Off-State Current I C(Off) V CE =4V. µa ERROR AMPLIFIER Threshold Voltage V th.3.. V Input Bias Current I IB IN-= V th na BLOCK ON Threshold Voltage V ON. V OFF Threshold Voltage V OFF. V Input Bias Current ( Terminal) I V =V µa GENERAL CHARACTERISTICS Standby Current I CCSTBY V =V 9 µa Operating Current I CC =nf, S I =V +, IN->V th, E S =GND. 4. ma (note) Output switch tests are performed under pulsed conditions to minimize power dissipation. Ver

4 TYPICAL APPLICATIONS Step-Down Converter R NJM344 C L R D R Step-Up Converter L D R C R NJM344 R Inverting Converter R D NJM344 C L R R Though the I decreases by inserting "R " to between terminal and terminal, the minimum operating voltage is increased due to the resister " R ". D use to schottky diode Ver.9--

5 TYPICAL APPLICATIONS Step-Down Converter (High Current) R BE R BC R L NJM344 C R F D R Step-Up Converter (High Current) L D R C R C R NJM344 R BE R Though the I decreases by inserting "R " to between terminal and terminal, the minimum operating voltage is increased due to the resister " R ". D use to schottky diode. Ver

6 TIMING CHART Error AMP Output Oscillator Waveform OSC Block to FF, NOR Switch Output Ipk Sense Output HIGH LOW ON OFF HIGH LOW - - Ver.9--

7 TYPICAL CHARACTERISTICS Oscillator Frequency vs. Timing Capacitor (V + =V, S I =V +, Pin =GND, Ta= o C) Switch TIme vs.timing Capacitor (V + =V, S I =V +, Pin =GND, Ta= o C) Oscillator Frequency f (khz) OSC Switch Time t, t (µs) ON OFF t ON t OFF Timing Capacitor (pf) Timing Capacitor (pf) Saturation Voltage V sat (V) Saturation Voltage vs. Collector Current (V + =V, C S =C D, Ta= o C) Input Bias Current I IB (na) Input Bias Current vs. IN- Terminal Voltage (V + =V, Ta= o C) Collector Current I C (A) IN- Terminal Voltage (V) Operating Current vs. Operating Voltage (C =nf, S=V +, IN->V, Es=GND, Ta= o C) 4 T I th Output Voltage vs. ON Threshold Voltage (V + =V, Vo=V, Io=mA, Ta= o C) Operating Current I CC (ma) 3 Output Voltage Vo (V) 4 3 Rc=Ω Rc=kΩ Rc=kΩ 3 4 Operating Voltage V + (V) ON Threshold Voltage Von (V) Ver

8 TYPICAL CHARACTERISTICS Input Bias Current vs. Terminal Voltage (V + =V, Vo=V, Io=mA, Ta= o C) Input Bias Current I on/off (ua) 4 3 Rc=Ω Rc=kΩ Rc=kΩ 3 4 Terminal Voltage V on/off (V) Threshold Voltage V th (V) Threshold Voltage vs. Temperature (V + =V). - - Discharge to Charge Ratio vs. Temperature (V + =V). Saturation Voltage vs. Temperature (V + =V, C S =C D, I SW =.A) Discharge to Charge Current Ratio I ratio Saturation Voltage V sat (V) Current Limit Sense Voltage V ipk (mv) Current Limit Sense Voltage vs. Temperature (V + =V) Operating Current I CC (ma) (V + =V, C =nf, S=V +, IN->V, Es=GND) T I th 4 3 Operating Current vs. Temperature Ver.9--

9 MEMO [CAUTION] The specifications on this databook are only given for information, without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. Ver