HT84063AREZ

HT84063A DC-to-DC Converter Control Circuits (compatible to MC34063) 1. DESCRIPTION The HT84063A is a monolithic control circuit containing the primary functions required for DC-to-DC converters. These devices consist of a internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. This series was specifically designed to be incorporated in Step-Down and Step-up and Voltage-Inverting applications with a minimum number of external components. 2. FEATURES • Operation from 3.0V to 40V Input • Low Standby Current • Current Limiting • Output Switch Current to 1.5A • Output Voltage Adjustable • Frequency Operation to 100kHz • Precision 2% Reference ORDERING INFORMATION HT84063ANZ DIP8 Block Diagram HT84063AREZ ESOP8 TA = 0 to 70C for all packages. Pin Connection 3. ABSOLUTE MAXIMUM RATINGS Rating Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage (VPIN1 = 40V) Switch Collector to Emitter Voltage Driver Collector Voltage Driver Collector Current (Note 1) Switch Current Operating Junction Temperature Operating Ambient Temperature Range Storage Temperature Range Symbol VCC VIR VC(switch) VE(switch) VCE(switch) VC(driver) IC(driver) ISW TJ TA Tstg Value 40 -30 to +40 40 40 40 40 100 1.5 +150 0 to +70 -65 to +150 Unit Vdc Vdc Vdc Vdc Vdc Vdc MA A o C o C o C Rev. 01 HT84063A 4. ELECTRICAL CHARACTERISTIC (Vcc=5.0V, TA= Tlow to Thigh , unless otherwise specified) Characteristics Symbol Min Typ OSCILLATOR 33 fosc 24 Frequency (Vpin5 = 0V, CT = 1.0nF, TA=25C) 35 ICHG 24 Charge Current (Vcc=5.0 to 40 V, T A=25C) 220 IDISCHG 140 Discharge Current (Vcc=5.0 to 40 V, T A=25C) Discharge To Charge Current Ratio IDISCHG/ ICHG 5.2 6.5 300 V 250 Current Limit Sense Voltage (ICHG= IDISCHG, TA=25C) ipk (sense) OUTPUT SWITCH Saturation Voltage, Darlington Connecttion (ISW=1A VCE(SAT) 1.0 Vcc=5.0V, pin 1, 8 connected) Saturation Voltage, Darlington Connecttion (ISW=1A VCE(SAT) 0.45 Vcc=5.0V, pin8 = 82) 75 hFE 50 DC Current Gain (ISW=1A Vcc=5.0V, TA=25C) 40 Collector Off-State Current (VCE=40V) IC(off) Max Unit 42 42 260 7.5 350 kHz 1.3 V 0.7 V 100 A COMPARATOR Threshold Voltage Vth 1.225 1.275 (TA=25C) 1.21 1.29 (TA =Tlow to Thigh) Threshold Voltage Line Regulation (Vcc=3.0V to 40V, Regline 1.4 5.0 TA=25C) Input Bias Current (VIN=0V) IIB -20 -400 TOTAL DEVICE Supply Current Icc 4.0 (Vcc = 5.0 V to 40 V, CT = 1.0 nF, Pin 7 = VCC, Vpin 5 > Vth, Pin 2 = Gnd, remaining pins open) Note: 1. Maximum package power dissipation limits must be observed 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible. A A mV V mV nA mA Rev. 01 HT84063A 5. TYPICAL PERFORMANCE CHARACTERISTICS Rev. 01 HT84063A 6. APPLICATION CIRCUIT 6.1 Step-up Converter 6.2 External Current Boost Connections for IC Peak Greater than 1.5A 6.2a External NPN Switch 6.2b External NPN Saturated Switch 6.3 Step-down Converter Rev. 01 HT84063A 6.3 Step-down Converter 6.4 External Current Boost Connections for IC Peak Greater than 1.5A 6.4a External NPN Switch 6.4b External NPN Saturated Switch Rev. 01 HT84063A 6.5 Voltage Inverting Converter 6.6 External Current Boost Connections for IC Peak Greater than 1.5A 6.6a External NPN Switch 6.6b External NPN Saturated Switch Rev. 01 HT84063A 7. Design Formula Table Calculation Step-Up Step-Down Voltage-Inverting Vout  VF - Vin(min) Vin(min) - Vsat Vout  VF Vin(min) - Vsat - Vout Vout  VF Vin  Vsat 1 fmin 1 fmin 1 fmin 4.0 x 10-5 ton 4.0 x 10-5 ton 4.0 x 10-5 ton   ton 2Iout(max)  1   toff 2Iout(max)   ton 2Iout(max)  1   toff RSC 0.3 / Ipk(switch) 0.3 / Ipk(switch) 0.3 / Ipk(switch) L(min)  Vin(min) - Vsat    ton(max)   Ipk(switch)   Vin(min) - Vsat - Vout    ton(max)  Ipk(switch)    Vin(min) - Vsat     ton(max)  Ipk(switch)  ton / toff (ton + toff)max CT Ipk(switch) CO 9 Iout ton Vripple(pp) Ipk(switch)(ton  toff) 8Vripple(pp) 9 Iout ton Vripple(pp) Terms and Definitions Vsat – Saturation voltage of the output switch. VF – Forward voltage drop of the output rectifier. The following power supply characteristics must be chosen: Vin – Nominal input voltage Vout – Desired output voltage. Iout – Desired output current. fmin – Minimum desired output switching frequency at the selected values of V in and IO Vripple(pp) – Desired peak-to-peak output ripple voltage. In practice, the calculated capacitor value will need to be increased due to its equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly affect the line and load regulation. Rev. 01 HT84063A DIP8 ESOP8 Rev. 01