AN6657

AN6657 PANASONIC | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 6

Technical content

The AN6657 and the AN6657S are the electronic gov- ernors capable of controlling the forward/reverse speed, fast forward, rewind, and start/stop of the micromotors used for the radio/cassette tape recorders, automatic an- swering telephone sets, and so on. n Features

• Wide operating supply voltage range ; VCC =4.5V to 14V
• Stable reference voltage (1.3V) and easy speed control
• Large starting torque and maximum control torque
• Good secular drift because of external power transistor
• Provided with the motor stop function ; ICC =20µA or less at stop time
• Capable of controlling forward/reverse rotation, fast for- ward/constant speed, and start/stop via 3 input pins n Applications
• Speed control of the micromotors for the radio cas- settes
• Speed control of the micromotors for the microcas- settes of the automatic answering telephone sets
• Control of the tape loading motors for the DATs, etc. AN6657, AN6657S Micromotor Forward/ Reverse Electronic Governors 8 21.7–0.3 1.2–0.25 3 ~ 15˚ Unit : mm 6.3–0.25 0.5–0.1 2.54 (3.45) 7.62–0.25 0.3 + 0.1 – 0.05 0.51min. 3.8–0.25 AN6657 16-Lead DIP Package (DIP016-P-0300E) 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 Amp. Drive Mode Swiching Logic Ref.Voltage 1kΩ 10kΩ GND V CC For./Rev. Drive Circuit n Block Diagrom Unit : mmAN6657S 0.3 1.5–0.2 0.65 0.15 10.1–0.3 6.5–0.3 4.2–0.3 16-Lead SOP Package (SOP016-P-0300)

ICs for MotorAN6657, AN6657S n Absolute M axim um R atings (Ta= 25˚C ) V C C IC C IO PD Topr Tstg Supply V oltage Supply C urrent O utput C urrent Pow er D issipation O perating A m bient Tem perature Storage Tem perature V m A m A m W Param eter Sym bol R ating U nit 14.4 700 500 380 –20 ~ + 70 –55 ~ +150 –55 ~ +125 A N 6657 A N 6657S A N 6657 A N 6657S n R ecom m ended O perating R ange (Ta = 25˚C ) Param eter Sym bol R ange O perating Supply V oltage R ange V C C 4.5V ~ 14V n Electrical C haracteristics (Ta = 25˚C ) V C C = 5V V C C = 5V V C C = 5V Supply voltage at w hich a 50m A current flow s to R a V C C = 4.5V , R a = 13Ω V C C = 5V , IL = 55m A , N = 2000rpm V C C = 5V , IL = 55m A , N = 2000rpm V C C = 5V , IL = 55m A , N = 4000rpm V C C = 4.5V ~ 9V , IL = 55m A V C C = 4.5V , IL = 55m A ~ 90m A V C C = 5V ~ 14V V C C = 5V ~ 14V V C C = 9V , R T = 1.3Ω V C C = 5V , Ta = 0˚C ~ 60˚C Param eter Sym bol C ondition m in. typ. m ax. U nit 1.3 0.62 0.015 B ias C urrent Prestart C urrent R eference V oltage Start V oltage Start C urrent R ated Load r.p.m Forw ard/R everse r.p.m D ifference FF/R ated r.p.m . R atio r.p.m . C haracteristics on V oltage C hange r.p.m . C haracteristics on Load C hange Sw itching M ode Input H Sw itching M ode Input L C urrent Lim iting Starting V oltage R ef. V oltage Tem perature C haracteristics Ibias Istop V ref V C C (S) IST N L ΔN Logi ΔN ΔN V ΔN L V H V L V Lim ΔV r/Ta m A µA V V m A Tim es rpm /V rpm V V V % /˚C 1.1 130 –10 1.85 0.55 1.5 2.15 120 0.7 0.7 M N C 4.3kΩ15kΩ 1kB 680Ω 2000 rpm /˚C 0.022µF 0.01µF 2SD 2249 or 2SD 2177 4.7µF 3900 rpm /˚C1.2Ω A N 6657, A N 6657S + – H K N –3A 6LD I (R a=13Ω ) (N ational M icrom otors C o., Ltd) To M echanism C ontroller, etc V C C 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 n Application Circuit

ICs for Motor AN6657, AN6657S n Pin D escriptions Equivalent C ircuitPin N o. Pin N am e V oltageD escription I/O

1 C onstant Speed

Setting C onstant speed setting pin O V C C – 1.3V 2 FF Setting FF speed setting pin O V C C – 1.3V

3 Speed C ontrol C ontrols the speed I

V C C To the pin 9. G N D N C Start/Stop Forw ard/R everse C onstant Speed/FF O scillation preventive phase com pensation pin M otor pin connection pin M oror pin connection pin V C C pin C onnect to the pin o. G N D pin N o connection Forw ard/reverse control pin C onstant speed/FF control pin I O O O O O I O I I I I C ollector connection pin of the external N PN transistor B ase connection pin of the external N PN transistor M otor torque load characteristics setting pin Start/stop control pin 40kΩ 30kΩ 50Ω 150Ω 70kΩ V R EF 11 985

ICs for MotorAN6657, AN6657S n Supplem entary Explanation

• Principle of Functioning T he A N 6657 and the A N 6657S are the electronic governors w hich control the m otor speed constantly by m aking use of the fact that the counter electrom otive force generated in the m otor w inding is proportional to the m otor speed w hen the D C m otor rotates. They have tw o m otor drive system s w hich correspond to the forw ard and reverse rotations, respectively. The inter-pin voltage of the m otor Em is given by the follow ing expression. Em = Ea + R a Ia Ea : M otor reverse electrom otive voltage R a : M otor internal resistor Ia : M otor current There are the follow ing relationships betw een the m otor reverse electrom otive voltage Ea and M otor speed, and m otor torque T and m otor current Ia, respectively. Ea = K a · N T = K T · Ia K a : M otor generation constant K T : M otor torque constant In the expression (1), the inter-pin voltage of the m otor Em includes the voltage R a · Ia w hich changes depending on m otor current Ia. The counter electrom otive voltage Ea is taken out by configuring the bridge circuit and used as a m otor speed signal. In Fig. 1, the m otor speed N (∝ m otor generated voltage Ea) in the m otor control state can be expressed by the follow ing form ula. + V C E SA T1 The expression (4) applies in case of m otor forw ard rotation, in w hich a current flow s from the m otor pin (5) to the m otor pin (8). The follow ing expression applies in case of m otor reverse rotation, in w hich a current flow s form the m otor pin (8) to the m otor pin (5). +V C E SA T2 V R EF : R eference voltage, R a : M otor internal resistor Ia : M otor current r2, r3 : D iffusion resistance in the IC , r4, r5 : R esistance for speed control r1 : Torque control R esistance V C E SA T1 : Forw ard/reverse drive circuit saturation voltage w hen m otor forw ard rotation is set V C E SA T2 : Forw ard/reverse drive circuit saturation voltage w hen m otor reverce rotation is set (1) Ea = V R EF r2 + r3
• r4 + r5 + r1r2 – R a Ia (4) (5) Ea = V R EF r2 + r3
• r4 + r5 + r1r2 – R a Ia Forw ard/ R everse C onstant Speed/ Fast Forw ard S/S 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 A m p. 0.022µF + – M N C V C C D rive M ode Sw itching Logic R eference V oltage Forw ard/ R everse D rive C ircuit 1kΩ 10kΩ 2SD 2249 or 2SD 2177 2SD 2249 or 2SD 2177 0.01µF r6 4.3kΩ 1kB 15kΩ 680Ω R aEa 4.7µF R a : M otor-coiled resistor Ea : M otor counter electrom otive voltage : O scillation preventive capacitor : Prevention of m otor noise

10 R a<

Fig.1 AN 6657/AN 6657S M otor C ontrol Basic C ircuit (2) (3)

ICs for Motor AN6657, AN6657S A s it is clear from the expression (4), r1r2/r3 – R a = 0, that is, w hen r1 = r3/r2÷R a is established, Ea (∝ m otor speed N ) becom es a constant value w ithout depending on the m otor current Ia (load torque T). This is also true for the expression (5).

• Sw itching the Various M odes The A N 6657 and the A N 6657S have five m otor drive m odes as show n in Table 1. Those m odes can be selected depending on the voltage H (3V to 6V ) and voltage L (0V to 0.7V ) signals applied to the input pins14, 15 and 16. 1) Forw ard/reverse sw itching : Forw ard/reverse rotation is sw itched over w hether a current flow s from the pin5 to the pin8 (forw ard rotation) or vice versa (reverse rotation). 2) Pow er-off (pause) m ode : turning off the constant current source inside the IC stops a current to the m otor and stops m otor. In this m ode, all the transistors of the IC are turned off and only a leak current (20µA ) is available. 3) Setting the m otor speed The m otor speed at constant speed tim e can be expressed by the expression (4). In the FF (R EW ) m ode, the pin2 is turned on and the first term of the expression (4) is ; + V C E SA T and the m otor speed N (m otor generated voltage Ea) is expressed as follow s. From the expression (4), the m otor speed at constant speed can be controlled w ith r4 and r5 (external V R s). From the expression (6), the m otor speed at the FF (R EW ) m ode can be controlled w ith r6. The torque control resistance r1 is im portant in setting the m otor rotating state. Select the resistance w hich satisfies the condition of the expression (7) w ithin a w orking tem perature range. If this condition is not satisfied, the m otor m ay have abnorm al rotation such as hunting, etc. R a is the copper coiled resistor of the m otor and has the tem perature characteristics of + 3,900r.p.m /˚C , Therefore, it is necessary to set the value of r1 so that the relationship in the expression (7) w ill be satisfied at the m inim um w orking tem perature. The diffusion resistance r3/r2 in the IC has the flat tem perature characteristics, and if the tem perature characteristics of r1 is adjusted to that of R a, + 3900 r.p.m /˚C , the value of the second term (r1r2r – R a) of the expressions (4) and (5) show s the flat tem perature characteristics and the torque characteristics of the m otor speed becom es constant w ithout depending on a tem perature. Fig. 2 and Fig. 3 show this relationship.
• Setting the External R esistor r1 r2 R a (r3/r2 = 1/10 for the A N 6657, A N 6657S) (7) L H H H H H L H L L L H H H L H L L H L H O FF O FF O FF O N O N Pin14 Pin15 Pin16 Pin2 Pin5 M otor + Pin8 M otor – Input O utput M otor D rive M ode Pow er O FF (pause) Forw ard (constant speed) R everse (constant speed) FF R EW Table 1 AN 6657/AN 6657S M ode Sw itching Table V R EF r2+r3 r3 · r5 r4 · r6 r4+r6 + r5 (6) Ea =V R EF · r5 + r1r2 – R a Ia Low Tem perature N orm al Tem perature H igh Tem perature TM (Torque) Fig. 2 r1 Tem perature C haracteristics < R a Tem pera- ture C haracteristics N (R .P.M .) r2+r3 r3 r4 · r6 r4+r6

ICs for MotorAN6657, AN6657S

• C urrent Lim iting Function The current lim itting function detects the voltage drop of the torque control resistance r1, operates the PN P transistor, and controls the input voltage of the am plifier in the IC to lim it the current. Lim iting the current can reduce the useless current at start and m otor lock tim e and prevent the supply voltage from dropping. T he lim ited current IL im is calculated by the follow ing expression. V Lim : V B EO N V oltage < 0.6V W hen r1 = 1.2Ω , from the expression (8) ILim is ; = V Lim r1ILim = 0.6V 1.2Ω ILim = 500m A A ll Tem peratures TM (Torque) Fig. 3. r1 Tem perature C haracteristics = R a Tem pera- ture C haracteristics (8)• Tem perature Com pensation of M otor Speed For the norm ally used m otor w ith core, the tem perature com pensation of the m otor speed can be done by using 3,900 r.p.m /˚C m etal coated or coiled resistor as the torque control resistance r1, and m etal coated resistor w ith a positive tem perature coefficient of about 2,000r.p.m /˚C as the speed control resistance r4. N (R .P.M .) 800 600 400 200 Pow er D issipation PD (m W ) 40 80 120 160 A m bient Tem perature Ta (˚C ) PD – Ta R .p.m . N (rpm ) 40 80 120 160 Load Torque T (g – cm ) r.p.m . Load Torque 4000 2000 n C haracteristics C urve A N 6657S A N 6657 FF/R EW V C C = 9V V C C = 6V C onstant Speed